Introduction
Plants are an immense source of complex chemical molecules exploited by humans in several fields, such as the cosmetics industry, the agri-food industry, and the pharmaceutical industry. The study of the use of plants in African pharmacopoeia and traditional medicine has led to the identification of many active ingredients in various drugs currently used in modern medicine [1]. The diversity of these natural molecules, which are not essential to the viability of plants, remains a mystery to scientists trying to decipher their role in nature. Similarly, elucidating the biosynthetic pathways leading to original natural products is an inexhaustible field of investigation for scientists. In Africa, the therapeutic properties of plants were well known empirically by our ancestors and parents. However, it must be noted that there is a lack of knowledge about the chemical composition of these medicines used daily by these populations for healthcare [2].
According to estimates by the World Health Organization (WHO), approximately 80% of the population in developing countries use traditional medicine, particularly herbal medicine, for their healthcare needs. In some continents, such as Africa and Asia, herbs are even used as the first line of treatment for conditions such as malaria, diabetes, hypertension, dermatoses, and, more recently, diseases caused by pathogens that can cause serious infections in people living with HIV/AIDS. In fact, more than 120 pharmaceutical products commonly used today are derived from plants, most of them from tropical regions of the world, including Africa [3].
Currently, there is an increase in the use of compounds of natural origin, justifying the increase in the production of certain aromatic and medicinal plants (AMP). Many of these MAPs are used for their essential oils (EOs), which are the result of the synthesis and accumulation of volatile organic compounds present in the form of tiny droplets in the leaves, bark, fruit, resin, branches, and roots [4].
Due to its location, Senegal has a biodiversity of prime importance with many plants of therapeutic interest. These are divided into several families, classified into several genera, including numerous species.
This is how we became interested in the species Chrysopogon Nigritanus of the genus Chrysopogon, subgenus Plantae, belonging to the family Poaceae of the class Liliopsida. It is an aromatic medicinal plant widely used in West Africa, particularly in Senegal.
In light of this, the objective of our work is to study and characterize the chemical compositions and evaluate the biological and pharmaceutical activities of several extracts from the Chrysopogon Nigritanus plant and the essential oil from its roots, to promote and rationalize their traditional uses.
This work involves first conducting a bibliographic review in the context of a comprehensive analysis involving an ethnobotanical study, the use of the C. Nigritanus plant in traditional medicine and other fields, as well as previous chemical, biological, and pharmacological studies.
- Presentation of the Chrysopogon nigritanus plant
1. General information about the C. Nigritanus plant family
To identify a plant, the first step is to know its family. Generally, a local flora is used for this purpose, which allows species to be identified based on observation, especially of the reproductive organs. These are considered stable and independent of ecological conditions, thus allowing for accurate and rigorous identification [5].
C. nigritanus is a species of the Poaceae family, also known as Gramineae, a cosmopolitan family that includes a large number of species and genera. It is of major economic importance to the development of humanity. Indeed, it provides highly nutritious foods (rice, corn, wheat, etc.), raw materials of great importance in the food industry (sugar cane, sorghum: Sorghum bicolor), in the paper industry (alfalfa: Stipa tenacissima), in perfumery (Vetiveria: Chrysopogon zizanioides, C. nemoralis, C. nigritanus), and as building materials (bamboo). In addition, certain species of this family are used in traditional medicine to treat various conditions such as inflammation, malaria, urinary tract infections, diarrhea, rheumatism, as an aphrodisiac and to facilitate childbirth [6].
The species in this family have a remarkable ability to adapt. They cover virtually all natural environments. The family comprises 13 subfamilies, around 800 genera, and more than 12,000 species. They are herbaceous plants, either perennial or annual, hermaphroditic, monoecious, or dioecious.
Characteristics that identify Poaceae:
- The leaves are generally linear, alternate, and distichous, and have a sheath split on the side opposite the blade. They usually have ligules and no petioles (bamboo has a false petiole).
- The stems, also called culms, are: round, sometimes oval, hollow or filled with pith, sometimes lignified and large (bamboo, reeds, etc.).
- The inflorescences are formed by spikelets grouped in spikes and panicles.
- The spikelet always has two bracts at its base, called glumes.
- Flowers: Each flower is surrounded by two glumes: the lemma and palea, the calyx and corolla, reduced to tiny organs.
- The fruit is a special type of achene: the pericarp and seed are fused, with no wall between them [7].
2. Ethnobotanical study of Chrysopogon nigritanus
a. Description of the plant
Chrysopogon nigritanus (Benth), better known by its taxonomic synonym Vetiveria nigritana, is a perennial grass species in the Poaceae family, monocotyledonous. Native to South Asia, it has been used for more than a century in India, Thailand, and sub-Saharan Africa [8]. It grows in dense clumps with short simple rhizomes and stands upright, reaching a height of about 2.4 meters. It features large, open, spreading purple panicles, composed of long, slender racemes, each with a fine stem and arranged in 8 to 10 whorls around a central axis, bearing numerous slender spikes with short, fine, scarcely visible awns, straight or slightly curved. The leaves are erect or ascending, forming an acute angle with the stem, long and linear, up to 1 m x 1 cm, and pale green. The stems are coarse and pale green-yellow, cylindrical in their upper part, and the roots are yellow, sometimes emerging from a short rhizome [9].
- Climate and environmental adaptation of the C. Nigritanus plant
A hygrophilous species, it grows in low floodplains and along the banks of rivers and ponds. This species bridges the gap between aquatic and terrestrial plants. Vetiver is also used because of its drought tolerance due to its ability to grow in infertile soils with extreme temperatures ranging from 14°C to 55°C. The plant tolerates drought, frost, salinity, metals, and other unfavorable chemical conditions in the soil [10, 11]. Although the plant is highly resistant to extreme soil and climate conditions, as mentioned above, it cannot tolerate shade at all. Shading reduces its growth and, in extreme cases, could even eliminate vetiver in the long term [10].
- Uses of the C. nigritanus plant
1. Ecological uses
C. Nigritanus is of interest for the conservation, stabilization, and elimination of certain trace metals (Al, As, Cd, Cu, Cr, Pb, Zn) from soils. It produces high levels of biomass, and its dense root system provides a large specific surface area and delimits a significant rhizosphere zone. It could therefore be used for the rehabilitation of arsenic-contaminated soils. [12] Rapid growth and high biomass are preferred criteria for selecting plants for phytoremediation, which is why it is a very promising candidate; It is used as an alternative to synthetic chemical pesticides. One of the special characteristics of vetiver is its ability to form a dense hedge when planted closely together. A vetiver hedge can withstand water flow of up to 0.6 m in depth, forming a vegetative barrier that retains and distributes runoff water. The vetiver hedge also acts as a highly effective filter, retaining sediments and agricultural chemicals before they reach waterways. It is also used for water treatment by removing trace metals from domestic wastewater in micro-phytostations [13, 14, 15]. Vetiver grass is introduced as a resilient forage alternative in the Mediterranean basin in the face of climate change, which poses a threat to the sustainability of forage crop production [16]. It has potential as a wood preservative against termites and wood borers [17].
2. Use in traditional medicine
The therapeutic use of medicinal plants dates back to ancient times in Africa, where they are more numerous than on any other continent. During the colonial period, these medicinal practices were suppressed, but today doctors often work in close collaboration with traditional healers. In traditional medicine, different parts of specific plants are used, including the leaves, bark, roots, fruits, or even the entire plant [18, 19].
In India
Native to India, vetiver has been used for several centuries as a medicinal and aromatic plant. Different parts of the vetiver plant are used for various purposes to treat conditions such as mouth ulcers, boils, epilepsy, burns, snake bites, scorpion stings, rheumatism, fever, headaches, and more. Fresh root paste heals burns, snake bites, and scorpion stings, and a decoction of the roots is used as a tonic against weakness.
The root extract is used for headaches and toothaches. The tribes of Varanasi and Oraon inhale the root vapors to treat malaria and use root ash to relieve acidity. Leaf pastes effectively relieve rheumatism, lower back pain, and sprains, and the dried roots are used to scent clothes [20, 22].
In Indonesia
Indonesia was the world’s leading producer of vetiver oil. The plant is used to treat symptoms and also for cosmetic purposes. For example, the roots are used to eliminate unpleasant body odors caused by sweating. It is also used to treat rheumatism.
In Pakistan
Vetiver, known under the names Khas, Aseer, or Daron, is widely used in traditional medicine to treat heart weakness, palpitations, fainting, and to counteract the harmful effects of air pollution. It is consumed in the form of syrup, powdered infusion, or drink to treat fever, inflammation, and stomach irritations [23]. Thanks to its cooling and astringent properties, and its ability to quench thirst, vetiver is also used as an antipyretic in cases of bilious and blood fevers. Vetiver oil is used to control vomiting in cholera, and the vapors from vetiver leaves burned with benzoin are effective in treating headaches caused by liver diseases [24].
In Thailand
Thais use vetiver roots to dissolve gallstones, reduce fever, treat liver and gallbladder conditions, and relieve stomach aches. Additionally, vetiver is used for medicinal purposes depending on the region. In the Pho Prathap Chang district of Phichit province, the properties of vetiver roots are used to treat stomach aches, reduce gas, and digestive disorders. The leaves are used to treat urinary problems, and the roots mixed with other plants in various ways are used to treat many ailments [23].
In Senegal
In traditional Senegalese medicine, there are many medicinal uses of V. Nigritana, many of which revolve around its aphrodisiac properties. It is also known and used as a water purifier (antiseptic), giving taste and fragrance, as well as for its antibacterial properties. Young women use a vetiver root infusion to relieve menstrual pain. After childbirth, the infusion is used to cleanse the reproductive system. It is recognized as an effective purifier for the feminine parts under stress. Vetiver is useful in skincare as an antiseptic, tonic, and detoxifier. Powdered vetiver roots are used as an astringent to speed up wound healing. The infusion of the roots in water is used to disinfect and eliminate pathogenic bacteria, and also for diarrhea in breastfeeding mothers and young infants [23-26].
The roots of this plant contain an essential oil with sesquiterpene alcohols responsible for its disinfectant and antiseptic properties. It has a pleasant smell and is widely used to disinfect drinking water. The latter is highly used and acts mainly on the nervous system, having both a calming and invigorating effect. It is excellent for treating depression, nervous tension, fatigue, insomnia, and many stress-related ailments, and acts as an aphrodisiac. It is also used in massages and baths to relieve stress, anxiety, nervous tension, and insomnia [27].
3. Uses in perfumery and cosmetics
In skincare, vetiver is used to balance sebum secretion and is also an effective antiseptic and mild astringent. It is used to treat oily skin, acne, oozing wounds, and serves as an antiseptic, tonic, and detoxifier [27]. That is why we now see soaps, facial creams, and scrubs made from this plant. Due to its rich, sensual, and deeply soothing fragrance, it is also called the oil of tranquility and the scent of the earth. Since the Middle Ages, it has been the most commonly used oil in perfumes. The cosmetic industry widely uses vetiver essential oil and its extracts. In diluted form, vetiver oil is used to provide a soft and calming note. Vetiver has been used as a raw material for various scented products such as perfumes, deodorants, lotions, soaps, cosmetics, and so on. It is soluble in several alcohols, which is an advantage in the field of perfumery [28].
Previous chemical and pharmaceutical work
The C. Nigritanus plant has not been studied extensively in terms of its chemical and pharmacological properties, but despite this, there are previous studies, and, according to our research, its essential oil is the most studied component.
1. Chemical studies on C. nigritanus
Vetiver has a very diverse chemical composition in its various parts, which explains its wide therapeutic use.
a. On the roots of C. nigritanus
Studies conducted on the aqueous extract and the isopropanol extract show that there are different families of secondary metabolites present in both extracts, distributed as follows: the presence of terpenes, polyphenols, flavonoids, and coumarins in both extracts; the presence of alkaloids, condensed tannins, and gallotannins in the aqueous extract; the absence of saponins in both extracts; and the absence of condensed tannins and gallotannins in the isopropanol extract. The determination of the polyphenol and flavonoid levels in the two extracts shows that these two extracts have virtually similar polyphenol contents, but the aqueous extract has a higher flavonoid content than the other extract [29]. Studies on the methanolic extract of the roots have determined the total polyphenol content and that of proanthocyanidins to be 5.7+/-0.47 GAE and 6.415+/-0.2 mg/g CE, respectively [30].
Analysis of fatty acids after saponification of the petroleum ether extract obtained from the rhizomes yielded an acid fraction which, after isolation and weighing, represented 64.95% of the extract; 84% of the constituents of this fraction could be identified and quantified. Classic fatty acids were noted, but also a significant proportion of sesquiterpene organic acids, which are characteristic of the Vétiveria genus (68.39%). Fatty acids constitute only 15.39% of the acid fraction; these are mainly saturated acids (9.49%), with palmitic acid (4.91%) as the main compound; unsaturated fatty acids are not very abundant (5.9%) [31]. The unsaponifiable fraction was also fractionated and, after isolation and weighing, was found to represent 21.57% of the extract, of which 73.07% of the constituents of this fraction have been identified, and the majority of compounds (54.8%) belong to the sesquiterpenoid group. These are mainly sesquiterpene alcohols (46.84%), including cedar-8-ene-15-ol and khusimol. The other compounds are divided between aldehydes (4.57%), ketones (1.88%), hydrocarbons (1.51%), and sterols (13.7%), which are sterols frequently found in the plant kingdom [31].
GC-MS analysis of the essential oil sample from the roots of C. Nigritanus cultivated in Sudan shows that the main components of the oil were sesquiterpene hydrocarbons and their oxygenated derivatives. Of the fifty compounds detected, forty-one were identified; the major product is longifène-D (25.1%), followed by 2-hydroxycypérol (9.7%) and aromadendrene oxide (8.8%). These results do not match the known fingerprint of vetiver oil, which contains more of the sesquiterpenes α-vetivone, β-vetivone, and khusimol [32].
Other studies on this oil from the roots of C. Nigritanus cultivated in Sudan revealed a total of 19 compounds, most of which were oxygenated sesquiterpenes (64.3%), with Cedr-8-en-15-ol (28.7%) as the main constituent. Sesquiterpene hydrocarbons accounted for 4% of the oil, while monoterpenes were not detected. Additionally, the alkane triacontane (20.1%) was found in relatively abundant amounts [33]
The chemical analysis of the essential oil extracted from the roots of V. nigritana from Burkina Faso made it possible to identify twenty-seven (27) compounds, among which the main components can be cited as dehydronigritene (24.24%), zizanoic acid (11.48%), preziza-7-(15)-en-3-ol (6.42%), khusimol + preziza-7(15)-en-12-ol (5.83%), khusian-2-ol (5.09%), ziza-6(13)-en-3-beta-ol (3.21%), prezizaan-15-al (3.00%), and khusimone (2.69%) [34]
In Mali, the analysis of root oils of V. nigritana by GC-MS revealed a varying composition of fifty-four constituents, with prezzanoic acid (15.0%), preziza-7(15)-en-12-ol (9.5%), cedren-8-en-15-ol (6.2%), preziza-7(15)-en-3α-ol (6.0%), and zizanoic acid (5.9%) being the main components. Among the constituents, two sesquiterpene hydrocarbons, dehydronigritene and nigritene, and two sesquiterpene acids, cedren-15-oic acid and 2-epi-prezzanoic acid, were confirmed by EI-MS and NMR [25].
Gas chromatography coupled with mass spectroscopy (GC-MS) analyses showed the presence of 36 compounds in the essential oil (EO) of Chrysopogon Nigritanus roots harvested in Senegal, specifically in Thiès [36].
By examining the mass spectra of the various products in the essential oil and the IR spectrum, we discovered that this oil contained: sesquiterpenes and sesquiterpenols in high concentrations, which was confirmed by IR and MS; the presence of sesquiterpene ketones was also noted by analyzing the MS, but the IR analysis did not confirm this presence. Acids such as isovalencenic acid and zizanoic or khusenic acid, as well as sesquiterpene esters such as andrographolide, which is a diterpene lactone, were also observed.
The variation in the chemical composition of essential oils from C. nigritanus roots could be attributed to the maturity of the plant, environmental factors, temperature, rainfall, and the season or month of harvest [33].
Analysis of the root oil collected in Benin by GC and GC-MS revealed sixty constituents, of which ledene oxide (52.1%), zizanoic acid (49.8%), hexadecanoic acid (43.5%), prezizanoic acid (29.1%), cedrol (43.6%), khusinol (23.0%), cedr-8-en-15-ol (21.5%), khusimol (14.8%), khusian-2-ol (14.0%), phytol (13.4%), and α-cedrene (16.1%) are the main components [37].
Phytoremediation studies of chromium-6 ions by vetiver roots carried out on samples from boreholes and wells in a given area in Senegal show that V. Nigritana roots can trap hexavalent chromium in water after 6 hours of contact. The percentage of elimination varies between 33.33% and 80%, and the amount of chromium adsorbed per unit mass of vetiver ranges from 0.003 to 0.008 mg/g [38].
b. On the aerial part of C. nigritanus
Fatty acid analysis after saponification and the constituents of unsaponifiables in petroleum ether extracts obtained from flowering tops and rhizomes were performed on the species growing in Mali, and the results show that after isolation, fatty acids represent 13.1% of the petroleum ether extract. 79.9% of the fatty acids were identified and quantified. It is noted that 71.5% are saturated fatty acids, among which palmitic acid (20.17%), lauric acid (8.76%), and myristic acid (7.11%) are the most abundant; unsaturated fatty acids (7.75%) are represented only by oleic acid (4.07%) and linoleic acid (3.68%). The presence of long-chain fatty acids, with 22 to 34 carbon atoms, as well as fatty acids with an odd number of carbon atoms, which are rarely found in the plant kingdom, was noted in this composition, as well as diacids (4%). [31]
For the flowering tops extract, the fraction after isolation and weighing represents 68.9% of the petroleum ether extract, and 82.56% of the constituents of this fraction have been identified. The main group of constituents is represented by sterols (43.89%), with two compounds being predominant, β-sitosterol and stigmasterol (18.36% and 10.08%, respectively), and cholesterol representing 1.64%. Saturated aliphatic hydrocarbons (C23 to C35) represent the second largest group of constituents (30.1%); of these, 24.79% are compounds with an odd number of carbon atoms, which is common in the plant kingdom.
Tocopherols account for 1.48% of the unsaponifiable matter, with the α-tocopherol isomer, which has high antioxidant activity, constituting about half of the total tocopherols. The presence of squalene is noted, although it is in small quantities (0.71%). Only one terpene derivative has been identified, fernenol, a compound reported in many species of Poaceae [31].
Studies on the aerial parts of V. nigritana have identified five flavonoid compounds [39]. The structures of the compounds were identified and confirmed by NMR as follows: carlinoside (1); neocarlinoside (2); 6,8-di-C-arabinopyranosylluteolin (3); isoorientin (4); and tricin-5-OH-glucoside (5). The same flavonoids were identified for the first time in both species, except for compound (4), which is only present in V. zizanoides.
These results showed that the aerial parts mainly contained 6,8-di-C-heterosides or luteolin. These flavonoids share a common structural component, which likely indicates the presence of a C-glycosidic step in the flavone biosynthesis pathway. Moreover, it should be noted that this is the first time that 6,8-di-C-arabinopyranosyl-luteolin has been isolated in the Poaceae family [39].
Previous pharmaceutical research on C. nigritanus
Pharmaceutical research on medicinal plants involves studying their biological properties to discover new drugs and explore their therapeutic potential.
c. Antioxidant activity of C. nigritanus
Antioxidants are widely used as food additives to protect foods from oxidative degradation by free radicals. They also have many beneficial effects on human health.
The antioxidant activity of C. Nigritanus roots was studied on the aqueous and isopropanol extracts using three methods: DPPH• free radical scavenging, CUPRAC method, and ABTS•+. The results obtained with the CUPRAC method revealed that the aqueous extract had the highest antioxidant capacity with 2.914 mg TE/g Ms, while that of the isopropanol extract was 0.925 mg TE/g Ms. The results of the DPPH• method show a 5.4% difference in inhibition in favor of the aqueous extract, and for the method using the ABTS•+ cation radical, the aqueous extract also shows the best result with an IC50 of 0.13 compared to 0.194 for the isopropanol extract. It also follows that the latter gives the best activity [29].
A comparative study of the anti-radical activity of essential oil from C. Nigritanus grown in the wild in Sudan with Chamaecyparis obtusa and Lavandula coronopifolia shows that, in 4 out of 6 tests (DPPH, ABTS, CUPRAC, FRAP, MCA, and PBD) that C. Nigritanus oil has the most significant anti-radical activity [33].
Studies on the anti-radical activity of essential oil from C. Nigritanus roots harvested in Burkina Faso confirm the existence of antioxidant activity in the latter, but it is somewhat weak compared to standards (ascorbic acid and quercetin). The highest IC50 was obtained with V. nigritana (28.35 µl) essential oil, and the lowest with quercetin (12.45 µl). Vétiveria nigritana essential oil had radical scavenging power, but this activity was lower than that of quercetin and ascorbic acid, but quite similar to that of butylated hydroxytoluene (BHT) (26.94 µl) [34].
Antioxidant tests we performed on essential oil from C. Nigritanus roots harvested in Senegal yielded positive results for the antioxidant activity of the latter, with an IC50 of 0.71mg/L for the DPPH• test and 1.6 mg/L for the ABTS•+ test, compared to 0.02 and 0.056 mg/L, respectively, for ascorbic acid, which was the standard [36].
Studies on some pharmacological properties of the methanolic extract of V. Nigritana roots compared with other plants in Togo by [30] show radical scavenging activity (DPPH method) with an IC50 of 5.7+/- 3.34µg/mL, which is higher than that of the standard, ascorbic acid. This activity was also correlated with the total polyphenol content and that of proanthocyanidins, with a GAE of 5.7+/-0.47 and EC of 6.415+/-0.2 mg/g, respectively.
The study on the ability of Vetiveria nigritana rhizomes to preserve food was conducted, and the results indicate that this plant would be the most suitable plant species as a preservative for syrup made from local plants. The use of Vetiveria nigritana rhizomes followed by hot packaging and canning allowed the product to be preserved for more than a year [26].
d. The antibacterial activity of the C. Nigritanus plant
The antimicrobial activity of the oil was evaluated against four pathogenic bacteria. Antibacterial activity varied, ranging from total resistance in Escherichia coli (inhibition zone of 0 mm) to significant activity in Pseudomonas aeruginosa (inhibition zone diameter of 23 mm). Two bacteria, Bacillus subtitis and Staphylococcus aureus, were less sensitive to the oil (15.5- and 11.3-mm inhibition diameter) [32].
The evaluation of the antibacterial activity of V. nigritana essential oil showed effectiveness against all the microbial strains studied. The inhibition diameters (ID) of the essential oil ranged from 8.5 mm (Salmonella infantis, Salmonella typhimurium, Shigella flexnerii) to 23.5 mm (Bacillus subtilis). A strong inhibitory action (ID ˃ 15 mm) was observed on strains of Bacillus, Clostridium perfringens, Escherichia coli ATCC 25922, and Staphylococcus hominis. A moderate inhibitory action (10 mm ≤ ID ≤ 15 mm) was observed on strains of Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Micrococcus luteus, Salmonella enteridis, Salmonella nigeria, Shigella dysenteriae, Staphylococcus aureus, Yersinia enterocolitica, Candida albicans, Kefir Candida, and Saccharomyces cerevisiae. For strains of Pseudomonas aeruginosa, Salmonella infantis, Salmonella typhimurium, Shigella flexnerii, and Candida tropicalis, a weak inhibitory effect was noted (DI ˂ 10 mm) sur les [34].
The same studies [20] also focus on antibacterial activity and show that the methanolic extract of C. nigritanus roots is active against only 3 out of 8 bacterial strains, namely Serratia mirabilis, Shigella flexneri and Salmonella enteritidis, with the same mean inhibitory concentration (MIC) of 1800 µg/L.
Studies have focused on the isolation and screening of bacteria on V. nigritana rhizomes harvested in Namibia. These roots were rinsed with sterile distilled water, then transferred to a phosphate-buffered saline solution and vortexed. Following this procedure, a bacterial isolate 100% similar to the Bacillus sp29 (2010) isolate was found [40].
e. Hemolytic activity
The hemolytic activity of the methanolic extract of C. Nigritanus roots was studied [30] using saponin R as a standard. The latter showed total hemolysis at concentrations above 6µg/mL, and by equating the concentrations of the extract used and saponin R, the results obtained are as follows: for 10µg/mL of vetiver extract, there is a hemolysis production equivalent to 1.5µg/mL of saponin R; for 100 µg/mL, 3 µg/mL is equivalent, and for 400 µg/mL, 5.25 µg/mL of the standard. Therefore, the results obtained with 400 µg/mL of C. nigritanus extract are somewhat close to total hemolysis.
f. Insecticide activities
A study was conducted on Vétiveria nigritana as a means of controlling termites on agricultural land in southwestern Nigeria. The results of this study found that vetiver is a complementary strategy to chemical control, and that specialists in natural products and bioprospecting should further investigate the termiticide potential of vetiver with a view to developing environmentally friendly termiticide formulations compatible with tropical agricultural systems [41].
Comparative studies on the use of the plant C. nigritanus as a pesticide compared to synthetic pesticides on two types of soils (lixisols and vertisols) show that in the presence of Vetiveria nigritana, there is a decrease in total microbial biomass of 0.3% and 32%, respectively. A decrease in soil respiratory activity of 31.6% and 10.72%, respectively, in lixisols and vertisols was noted compared to the control (soil without pesticides). These preliminary results further highlight the importance of the presence of the plant species with its inhibitory effect on respiratory activity regardless of soil type [15].
Conclusion
In summary, it can be said that the plant C. Nigritanus is not yet widely exploited from a pharmaco-chemical point of view. Research indicates that it has a rich chemical composition and pharmaceutical activities such as antioxidant, antibacterial, hemolytic, and insecticidal properties. Although the rhizomes have been studied more extensively and their properties are better known to users of the plant, studies have also been conducted on its aerial parts. In the next phase of our work, we will deepen our research to try to exploit the plant’s benefits to the fullest scientifically by building on work already done on other organic extracts, but also by focusing more on other chemical studies, such as alkaloid dosage, analysis, isolation, and structural identification of other molecules. We will also evaluate other pharmaceutical activities such as anti-inflammatory, antifungal, antiviral and insecticidal activity, test for minerals to assess its mineral composition, and verify the toxicity of the C. Nigritanus plant.
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