Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus

Uncovering the pharmacological mechanisms of Patchouli essential oil for treating ulcerative colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Pogostemonis Herba has long been used in traditional Chinese medicine to treat inflammatory disorders. Patchouli essential oil (PEO) is the primary component of Pogostemonis Herba, and it has been suggested to offer curative potential when applied to treat ulcerative colitis (UC). However, the pharmacological mechanisms of PEO for treating UC remain to be clarified.

AIM OF THE STUDY

To elucidate the pharmacological mechanisms of PEO for treating UC.

METHODS AND RESULTS

In the present study, transcriptomic and network pharmacology approaches were combined to clarify the mechanisms of PEO for treating UC. Our results reveal that rectal PEO administration in UC model mice significantly alleviated symptoms of UC. In addition, PEO effectively suppressed colonic inflammation and oxidative stress. Mechanistically, PEO can ameliorate UC mice by modulating gut microbiota, inhibiting inflammatory targets (OPTC, PTN, IFIT3, EGFR, and TLR4), and inhibiting the PI3K-AKT pathway. Next, the 11 potential bioactive components that play a role in PEO's anti-UC mechanism were identified, and the therapeutic efficacy of the pogostone (a bioactive component) in UC mice was partially validated.

CONCLUSION

This study highlights the mechanisms through which PEO can treat UC, providing a rigorous scientific foundation for future efforts to develop and apply PEO for treating UC.

Antimicrobial Activity on Streptococcus mutans and Enterococcus faecalis of Cyperus articulatus Ethanolic Extracts

Oral diseases are one of the biggest public health problems worldwide, caused by opportunistic pathogens such as Streptococcus mutans and Enterococcus faecalis. Cyperus articulatus (priprioca) is a plant conventionally used in traditional medicine in the Amazon region. However, little is known about the possible dentistry-related uses of extracts from the rhizomes and solid waste generated by the extraction of essential oils from this vegetable. This study aimed to investigate the chemical composition of volatile compounds and antimicrobial activity through the Minimum Inhibitory Concentration test (MIC and assessment of the toxicity by Hens Egg Test-Chorion Allantoic Membrane (HET-CAM) of the ethanolic extracts from Cyperus articulatus intact rhizomes and solid waste. We identified sesquiterpenes as the main constituents, strong antimicrobial activity of the ethanolic extract of intact rhizomes against S. mutans (MIC = 0.29 mg/mL), moderate antimicrobial activity against E. faecalis of the extract obtained from the solid waste (MIC = 1.17 mg/mL), and absence of toxicity for both tested extracts. The absence of irritation and the antibacterial activity of the ethanolic extract from C. articulatus rhizomes and solid waste reveal its potential for use in the alternative control of bacteria that cause oral infections and may present economic viability as a raw material for dental products.

Potential of medicinal plants as antimalarial agents: a review of work done at Kenya Medical Research Institute

Background: Medicinal plants have traditionally been used as remedies against malaria. The present review attempted to compile data on scientific research evidence on antimalarial medicinal plants screened at Kenya Medical Research Institute (KEMRI), Center for Traditional Medicine and Drug (CTMDR) Research from January 2003 to December 2021. Methods: A systematic review was conducted using a predefined protocol based on PRISMA. Search was performed in Google Scholar and PubMed. One hundred and eight journal articles were identified 37 of which published on antimalarial/antiplasmodial work. Thirty journal articles with at least one author from KEMRI-CTMDR and accessible in full were selected for analysis. Relevant data was captured in MS Excel format and descriptive statistics, percentages and tables used to summarize the findings. Results: Assessment of individual plant species was considered as an independent study resulting in 1170 antiplasmodial/antimalarial tests done from 197 plant species. One hundred and fifty plant species were screened in vitro, one in vivo and 46 were both in vivo and in vitro. Three hundred and forty-four of tests reported good activity (IC50 < 10 μg/mL or parasite suppression rate of ≥50%), 414 moderate activity (IC50 values of 10-49 μg/mL or parasite suppression rate of 30%-49%) and 412 were reports of inactivity (IC50 ˃ 50 μg/mL or parasite suppression rate of <30%). Fuerstia africana and Ludwigia erecta were reported to have the highest activities, with IC50 < 1 μg/mL against Plasmodium falciparum D6 strain and chemosuppression in mice at an oral dose of 100 mg/kg, was reported as 61.9% and 65.3% respectively. Fifty five antimalarial/antiplasmodial active compounds isolated from eight plant species were reported with resinone (39) having the best activity (IC50 < 1 μg/mL). Conclusion: Though 344 of tests reported promising antimalarial activity, it was noted that there was limited evaluation of these plants in animal models, with only 9.0% (105/1170) studies and no clinical trials. This highlights an important research gap emphasizing the need for drug development studies that aim to progress study findings from preclinical to clinical studies. There is still need for extensive research on promising plant species aimed at developing new plant based antimalarial drugs.

Chemical Composition and Antiproliferative Activity of the Ethanolic Extract of Cyperus articulatus L. (Cyperaceae)

Cyperus articulatus L. (Priprioca) is a plant of the Cyperaceae family traditionally used in traditional medicine in the Amazon region. Studies of the essential oil of this species have identified many terpene compounds. However, little is known about the possible uses of solid waste generated by the extraction of essential oils. This study aimed to investigate the chemical composition of volatile compounds and to evaluate the antiproliferative activity of the ethanolic extract of solid residues generated by the extraction of the essential oil of C. articulatus L. rizhomes in experimental models in vitro using peritoneal macrophages of mice and human tumor cell lines. The analysis of the chemical composition of volatile compounds indicated the presence of sesquiterpenes and particularly sequiterpenic ketones as main constituents. The results showed that the treatment with ethanolic extract of C. articulatus L. reduced the activity of the enzyme arginase and proliferation of cancer cells (p < 0.0001). The extract also showed no cytotoxicity in macrophages in concentrations between 12.5; 25 and 50 mg/mL (p < 0.0001). The results indicated that the extract of C. articulatus L. exerts antiproliferative activity (p < 0.0001) with low toxicity on healthy cells in experimental models in vitro.

Chemical Composition and In Vitro Antiplasmodial Activity of the Ethanolic Extract of Cyperus articulatus var. nodosus Residue

Cyperus articulatus L. is popularly known as priprioca. Its rhizomes are used as a medicine in the treatment of malaria in traditional medicine. Since priprioca oil is extracted for commercial purpose, we evaluated if the components from the priprioca residue can be a source of antiplasmodial active molecules. This study aimed to determine the in vitro antiplasmodial and cytotoxicity activities of the ethanolic extract of C. articulatus as an in vitro antiplasmodial agent. From the solid residue of the plant rhizomes, 40 g samples were removed and subjected to hot extraction using a Soxhlet extractor. The in vitro antiplasmodial activity was determined using the W2 and 3D7 strains of P. falciparum. The phytochemical study identified the following main compounds: corymbolone (14.25%), cyclocolorenone (9.75%), and cadalene (8.36%). The extract exhibited moderate IC₅₀ (inhibitory concentration) against the two strains of P. falciparum: 1.21 ± 0.01 against the W2 strain and 1.10 ± 0.06 µg/mL against the 3D7 strain. Our results show the therapeutic potential of priprioca residue as a low-cost antiplasmodial agent.

Cyperus articulatus L. (Cyperaceae) Rhizome Essential Oil Causes Cell Cycle Arrest in the G2/M Phase and Cell Death in HepG2 Cells and Inhibits the Development of Tumors in a Xenograft Model

Cyperus articulatus L. (Cyperaceae), popularly known in Brazil as “priprioca” or “piriprioca”, is a tropical and subtropical plant used in popular medical practices to treat many diseases, including cancer. In this study, C. articulatus rhizome essential oil (EO), collected from the Brazilian Amazon rainforest, was addressed in relation to its chemical composition, induction of cell death in vitro and inhibition of tumor development in vivo, using human hepatocellular carcinoma HepG2 cells as a cell model. EO was obtained by hydrodistillation using a Clevenger-type apparatus and characterized qualitatively and quantitatively by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID), respectively. The cytotoxic activity of EO was examined against five cancer cell lines (HepG2, HCT116, MCF-7, HL-60 and B16-F10) and one non-cancerous one (MRC-5) using the Alamar blue assay. Cell cycle distribution and cell death were investigated using flow cytometry in HepG2 cells treated with EO after 24, 48 and 72 h of incubation. The cells were also stained with May–Grunwald–Giemsa to analyze the morphological changes. The anti-liver-cancer activity of EO in vivo was evaluated in C.B-17 severe combined immunodeficient (SCID) mice with HepG2 cell xenografts. The main representative substances of this EO sample were muskatone (11.6%), cyclocolorenone (10.3%), α-pinene (8.26%), pogostol (6.36%), α-copaene (4.83%) and caryophyllene oxide (4.82%). EO showed IC₅₀ values for cancer cell lines ranging from 28.5 µg/mL for HepG2 to >50 µg/mL for HCT116, and an IC₅₀ value for non-cancerous of 46.0 µg/mL (MRC-5), showing selectivity indices below 2-fold for all cancer cells tested. HepG2 cells treated with EO showed cell cycle arrest at G₂/M along with internucleosomal DNA fragmentation. The morphological alterations included cell shrinkage and chromatin condensation. Treatment with EO also increased the percentage of apoptotic-like cells. The in vivo tumor mass inhibition rates of EO were 46.5–50.0%. The results obtained indicate the anti-liver-cancer potential of C. articulatus rhizome EO.

The in vitro and in vivo anti-hepatotoxic, anti-hepatitis B virus and hepatic CYP450 modulating potential of Cyperus rotundus

In the present study we investigated the hepatotoprotective, hepatitis B virus (HBV) inhibitory and hepatic CYP450 enzyme (CYP3A4) modulatory potential of Cyperus rotundus rhizome fractions. The crude ethanol-extract, including different organic and aqueous fractions were tested for in vitro cytoprotection on HepG2 cells (MTT assay), followed by in vivo evaluation in Wistar rats (serum biochemistry and lipid profile). The in vitro anti-HBV activity was tested on HepG2.2.15 cells (HBsAg and HBeAg Elisa). Of these, the n-butanol and aqueous fractions showed the most promising, dose-dependent hepatoprotection in DCFH-injured HepG2 cells. Further, in CCl₄-injured rats, oral administration of C. rotundus (100 and 200 mg/kg·bw/day) significantly normalized serum markers of healthy liver function (SGOT, SGPT, GGT, ALP and bilirubin) and lipid profile (cholesterol, HDL, LDL, VLDL, TG and MDA), including tissue NP-SH and TP levels. Compared to other fractions, the ethyl acetate, n-butanol and aqueous fractions exhibited the best inhibitory effects on viral HBsAg and HBeAg secretions in dose- and time-dependent manner. In addition, reporter gene assay (Dual-luciferase) of transfected HepG2 cells showed mild activation of nuclear PXR-mediated CYP3A4 gene by the three active fractions. Taken together, C. rotundus showed very promising hepatoprotective and anti-HBV potential in experimental settings. In addition, this is the first report on modulation of CYP3A4 by C. rotundus that suggests its safe consumption in relation to drug metabolism and efficacy. Our data could therefore, provide the basis for the ethnobotanical medicinal use of C. rotundus in metabolic liver disorder and hepatitis B patients.

Review on medicinal plants and natural compounds as anti-Onchocerca agents

Onchocerciasis is a filarial vector borne disease which affects several million people mostly in Africa. The therapeutic approach of its control was based on a succession of drugs which always showed limits. The last one: ivermectin is not the least. It was shown to be only microfilaricidal and induced resistance to the human parasite Onchocerca volvulus. The approach using medicinal plants used in traditional medicine is a possible alternative method to cure onchocerciasis. Onchocerca ochengi and Onchocerca gutturosa are the parasite models used to assess anthelmintic activity of potentially anthelmintic plants. Numerous studies assessed the in vitro and/or in vivo anthelmintic activity of medicinal plants. Online electronic databases were consulted to gather publications on in vitro and in vivo studies of anti-Onchocerca activity of plants from 1990 to 2017. Globally, 13 plant families were investigated for anti-Onchocerca activity in 13 studies. The most active species were Anacardium occidentale, Euphorbia hirta and Acacia nilotica each with an LC₅₀ value of 2.76, 6.25 and 1.2 μg/mL, respectively. Polycarpol, voacamine, voacangine, ellagic acid, gallic acid, gentisic acid, 3-O-acetyl aleuritolic acid and (-)-epigallocatechin 3-O-gallate were the isolated plant compounds with anti-Onchocerca activity. Most of the assessed extract/compounds showed a good safety after in vivo acute toxicity assays and/or in vitro cytotoxicity test. The exception was the ethanol extract of Trichilia emetica, which killed completely and drastically mice at a dose of 3000 mg/kg. Several plant groups of compounds were shown active against Onchocerca sp. such as tannins, alkaloids, triterpenoids and essential oils. Nevertheless, none of the active compounds was subjected to clinical trial, to assessment of its diffusibility through nodular wall or its capability to induce genetic resistance of Onchocerca sp.

Anticonvulsant effect of ethanolic extract of Cyperus articulatus L. leaves on pentylenetetrazol induced seizure in mice

Cyperus articulatus (CA) rhizomes have demonstrated different properties on nervous system. However, the leaves still have not studied to treat epilepsy. The aim of this study was to determine the effect of CA ethanolic extract on pentylenetetrazol (PTZ) induced seizures in mice as well as measuring its antioxidant activity in vivo and in vitro. Mice were divided into five groups: (1) control (PTZ 80 mg/kg; i.p.), (2) PTZ-Diazepam (1 mg/kg; i.p.), (3-5) PTZ-CA 50, PTZ-CA 150 and PTZ-CA 300 (50, 150 and 300 mg/kg of CA extract, 30 min prior to each PTZ injection). The PTZ-CA 150 group showed lower seizure scores (P < 0.01), latency (P < 0.01), frequency (P < 0.01) and duration (P < 0.01) than control group. The antioxidant activity of CA extract scavenged DPPH radical showed IC 50 = 16.9 ± 0.1 μg/mL and TEAC = 2.28 ± 0.08, mmol trolox/g of extract, the content of gamma amino butyric acid (GABA) and malondialdehyde (MDA) were significantly high (P < 0.01) at dose of 150 mg/kg (82 ± 1.2 ng/g tissue; 1.0 ± 2.2 mol/g tissue, respectively). The present research demonstrated that CA extract possesses a potential effect to prevent PTZ induced seizures, antioxidant activity in addition to increase GABA levels.

Ethnobotanical survey of medicinal plants used as anthelmintic remedies in Gabon

ETHNOPHARMACOLOGICAL RELEVANCE

In this article, we report on an ethnobotanical survey realized at the Peyrie market in Libreville on Gabonese medicinal plants used to treat helminthiasis. While several alerts about cases of resistance to conventional anthelmintic treatments are causing to fear a public and animal health issue, the search for new sources of active compounds becomes an urgent issue. In Gabon like in many developing countries, people regularly turn to traditional medicine in case of physical ailments and/or spiritual healing therapies.

MATERIALS AND METHODS

To determine which medicinal plants are traditionally used by the populations of Libreville to fight against nematodes, medicinal plant traders were interviewed with standardized questionnaires. The surveys were conducted in the main market of Libreville. Ethnobotanical data such as frequency and percentage of families, species, administrations pathways, modes of preparations and parts of plants used were analyzed and summarized.

RESULTS

Thirty-four (34) traders were interviewed belonging to five (5) different ethnic groups. Twenty-four 24 plants used to treat intestinal, cutaneous and ocular helminthiasis were listed. The healers mainly turned towards to ligneous species. The parts of the plant used are mostly leaves and trunk bark. Most of the traditional remedies are prepared directly in water and four (4) principal routes were used for administration namely, oral, rectal, ocular and dermal.

CONCLUSION

This study allowed us to list anthelmintic species which will be subjected to a series of chemical and pharmacological assays.

Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities

ETHNO-PHARMACOLOGICAL RELEVANCE

Cyperus rotundus L. (Cyperaceae) is a medicinal herb traditionally used to treat various clinical conditions at home such as diarrhea, diabetes, pyresis, inflammation, malaria, and stomach and bowel disorders. Currently, it is one of the most widespread, problematic, and economically damaging agronomic weeds, growing wildly in various tropical and subtropical regions of the world. The present paper summarizes the available information that will aid in future medicine preparation by identifying active ingredients and their mode of action for a specific therapeutic activity using the latest technologies.

MATERIAL AND METHOD

This review article is based on the information available on the phytochemical, toxicological, and pharmacological studies on and traditional uses of C. rotundus. The present paper covers the literature available particularly from 2000 to 2015 online (Google Scholar, PubMed, ScienceDirect, Scopus, SpringerLink, and Web of Science) and in books on phytochemistry, ethnopharmacology, and botany of this plant.

RESULTS

Phytochemical and pharmacological studies revealed the significance of C. rotundus as an antiandrogenic, antibacterial, anticancerous, anticonvulsant, antidiabetic, antidiarrheal, antigenotoxic, anti-inflammatory, antilipidemic, antimalarial, antimutagenic, antiobesity, antioxidant, anti-uropathogenic, hepatoprotective, cardioprotective, neuroprotective, and nootropic agent. This is the most investigated plant worldwide due to the higher concentration of active ingredients in the form of essential oils, phenolic acids, ascorbic acids, and flavonoids in the tuber and rhizomes. Unfortunately, this significant plant species has not been assessed under improved cultivation conditions with the aim of conservation in natural habitats and high quality.

CONCLUSION

Reports can be found on the ehtnobotanical use of C. rotundus in atherosclerosis, aging, apoptosis, cancer, cystitis, epilepsy, hirsutism, nociception, prostatitis, and genotoxicity disorders. The phytochemical and pharmacological activities of C. rotundus have supported its traditional as well as prospective uses as a valuable Ayurvedic plant. Previous researches focuses on the phytochemistry, biological properties and clinical application of rhizomes and tubers of C. rotundus. However, such studies on the other parts of this medicinally important plant are still quest to be investigate. Furthermore, future study should aim at confirming the clinical activities and safety of this plant before being used for the development of new therapeutic agent in human subjects.

In vitro antimalarial activity of different extracts of Eremostachys macrophylla Montbr. & Auch

Introduction:The risk of drug resistance and the use of medicinal plants in malaria prevention and treatment have led to the search for new antimalarial compounds with natural origin.

Methods:In the current study, six extracts with different polarity from aerial parts and rhizomes of Eremostachys macrophylla Montbr. & Auch., were screened for their antimalarial properties by cell-free β-hematin formation assay.

Results: Dichloromethane (DCM) extracts of both parts of plant showed significant antimalarial activities with IC₅₀ values of 0.797 ± 0.016 mg/mL in aerial parts and 0.324 ± 0.039 mg/mL in rhizomes compared to positive control (Chloroquine, IC₅₀ = 0.014 ± 0.003 mg/mL, IC₉₀ = 0.163 ± 0.004 mg/mL). Bioactivity-guided fractionation of the most potent part (DCM extract of rhizomes) by vacuum liquid chromatography (VLC) afforded seven fractions. Sixty percent ethyl acetate/n-hexane fraction showed considerable antimalarial activity with IC₅₀ value of 0.047 ± 0.0003 mg/mL.

Conclusion: From 6 extracts with different polarity of E. macrophylla,s aerial parts and rhizomes, the DCM extract of both parts were the most active extract in this assay. The preliminary phytochemical study on the VLC fractions of the most potent part persuades us to focus on purifying the active components of these extracts and to conduct further investigation towards in vivo evaluation.

Anti-onchocerca Metabolites from Cyperus articulatus: Isolation, In Vitro Activity and In Silico 'Drug-Likeness'

The aims of this investigation were to isolate active ingredients from the roots/rhizomes of Cyperus articulatus used as herbal medicine in Cameroon for the treatment of human onchocerciasis and to assess the efficacy of the metabolites on the Onchocerca worm. The antifilarial activity was evaluated in vitro on microfilariae (Mfs) and adult worms of the bovine derived Onchocerca ochengi, a close relative of Onchocerca volvulus. Cytotoxicity was assessed in vitro on monkey kidney epithelial cells. The structures of the active compounds were determined using spectroscopic methods and their drug-likeness evaluated using Lipinski parameters. Two secondary metabolites, AMJ1 [containing mustakone (1) as the major component] and linoleic acid or (9Z,12Z)-octadeca-9,12-dienoic acid (2) were isolated. Both compounds were found to kill both the microfilariae and adult worms of O. ochengi in a dose dependent manner. The IC50s for AMJ1 were 15.7 µg/mL for Mfs, 17.4 µg/mL for adult males and 21.9 µg/mL for adult female worms while for linoleic acid the values were, 15.7 µg/mL for Mfs, 31.0 µg/mL for adult males and 44.2 µg/mL for adult females. The present report provides the first ever evidence of the anti-Onchocerca efficacy of AMJ1 and linoleic acid. Thus, these secondary metabolites may provide a lead for design and development of new antifilarial agents.

Anti-Onchocerca activity and phytochemical analysis of an essential oil from Cyperus articulatus L

BACKGROUND

The lack of a safe and effective adult worm drug and the emergence of resistant animal parasite strains to the only recommended drug, the microfilaricide, ivermectin put many at risk of the devastating effects of the onchocerciasis. The present study was undertaken to investigate the acclaimed anti-Onchocerca activity of the roots/rhizomes of Cyperus articulatus in the traditional treatment of onchocerciasis in North Western Cameroon and to assess the plant as a new source of potential filaricidal lead compounds.

METHODS

Crude extracts were prepared from the dried plant parts using hexane, methylene chloride and methanol. The antifilarial activity was evaluated in vitro on microfilariae (Mfs) and adult worms of the bovine derived Onchocerca ochengi, a close relative of Onchocerca volvulus. The viabilities of microfilariae and adult male worms were determined based on motility reduction, while for the adult female worms the viability was based on the standard MTT/formazan assay. Cytotoxicity of the active extract was assessed on monkey kidney epithelial cells in vitro and the selectivity indices (SI) were determined. Acute toxicity of the promising extract was investigated in mice. Chemical composition of the active extract was unraveled by GC/MS analysis.

RESULTS

Only the hexane extract, an essential oil exhibited anti-Onchocerca activity. The oil killed both the microfilariae and adult worms of O. ochengi in a dose manner dependently, with IC50s of 23.4 μg/ml on the Mfs, 23.4 μg/ml on adult male worms and 31.25 μg/ml on the adult female worms. Selectivity indices were 4, 4, and 2.99 for Mfs, adult males and adult females, respectively. At a single limit dose of 2000 mg/kg body weight, none of 6 mice that received the essential oil by gavage died. GC/MS analysis revealed the presence of terpenoids, hydrocarbons and fatty acids or fatty acid derivatives as components of the oil.

CONCLUSIONS

The essential oil from the roots/rhizomes of Cyperus articulatus is active against O. ochengi microfilariae and adult worms in vitro in a dose dependent manner, hence may provide a source of new anti-filarial compounds. The results also support the traditional use of C. articulatus in the treatment of human onchocerciasis.

Antiplasmodial potential of selected medicinal plants from eastern Ghats of South India

Malaria caused by the protozoan parasite Plasmodium falciparum, is a major health problem of the developing world. In the present study medicinal plants from Eastern Ghats of South India have been extracted with ethyl acetate and assayed for growth inhibition of asexual erythrocytic stages of chloroquine (CQ)-sensitive (3D7) and (CQ)-resistant (INDO) strains of P. falciparum in culture using the fluorescence-based SYBR Green I assay. Studied extracts showed a spectrum of antiplasmodial activities ranging from (a) very good (IC(50)<10-10 μg/mL: Cyperus rotundus and Zingiber officinale); (b) good (IC(50), >10-15 μg/mL: Ficus religiosa and Murraya koenigii); (c) moderate (IC(50)>15-25 μg/mL: Ficus benghalensis); (d) poor activity (IC(50)>25-60 μg/mL) and (e) inactive (IC(50)>60 μg/mL). Resistance indices ranging from 0.78 to 1.28 suggest that some of these extracts had equal promise against the CQ resistant INDO strain of P. falciparum. Cytotoxicity assessment of the extracts against HeLa cell line using MTT assay revealed that the selectivity indices in the range of 3-15 suggesting a good margin of safety.

Aroma evaluation of gamazumi (Viburnum dilatatum) by aroma extract dilution analysis and odour activity value

INTRODUCTION

Viburnum dilatatum (gamazumi) is widely distributed in Japan and China. Recently, juice from V. dilatatum fruits has been manufactured in Japan. Concerning the aroma of V. dilatatum, phenethyl alcohol, 3Z-hexenol and l-linalool have been identified in the essential oil from the flowers of V. dilatatum, however, there are no detailed reports on the aroma of V. dilatatum elucidated using sensory evaluation.

OBJECTIVE

To clarify odourants contributing to the characteristic aroma, the aroma extract dilution analysis (AEDA) method was performed through gas chromatography olfactometry (GC-O) analysis.

METHODOLOGY

The aroma-active compounds were identified by GC-O and AEDA, and in order to determine the relative contribution of each compound to the aroma of V. dilatatum, odour activity value (OAV) has been used.

RESULTS

The hydrodistillation of the leaf and branch of V. dilatatum afforded pale yellowish oils, with yields of 0.008 and 0.015% (w/w). The main components of the leaf oil were 3Z-hexenal (12.7%) and linalool (10.8%). In branch oil, palmitic acid (18.3%) and linoleic acid (8.2%) were identified. With regard to aroma components, 24 and 14 compounds were identified in the leaf and branch oils respectively, by GC-O analysis.

CONCLUSION

On the basis of AEDA, OAVs and sensory evaluations, nonanal is estimated as the main aroma compound of leaf and branch oil, as the other aroma compounds, C₆ compounds and 2-pentyl furan make green odour; linalool, eugenol and β-ionone play important role in the sweet odour of leaf oil. In branch oil, cis-furanlinalool oxide and eugenol make sweet odour, and β-eudesmol contributes to woody odour.

Antimalarial compounds isolated from plants used in traditional medicine

Objectives

This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given for substances with IC50 values ≤ 11 μM.

Key findings

Malaria is a major parasitic disease in many tropical and subtropical regions and is responsible for more than 1 million deaths each year in Africa. The rapid spread of resistance encourages the search for new active compounds. Nature and particularly plants used in traditional medicine are a potential source of new antimalarial drugs as they contain molecules with a great variety of structures and pharmacological activities.

Summary

A large number of antimalarial compounds with a wide variety of structures have been isolated from plants and can play a role in the development of new antimalarial drugs. Ethnopharmacological approaches appear to be a promising way to find plant metabolites that could be used as templates for designing new derivatives with improved properties.

Anti-plasmodial activity of the extracts of some Kenyan medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

The spread of drug resistant Plasmodium falciparum strains necessitates search for alternative newer drugs for use against malaria. Medicinal plants used traditionally in preparation of herbal medicines for malaria are potential source of new anti-malarial drugs.

AIM OF THE STUDY

To identify the anti-plasmodial potential of twelve plants used in preparing herbal remedies for malaria in Kilifi and Tharaka districts of Kenya.

MATERIALS AND METHODS

Twelve plants used traditionally for anti-malarial therapy in Kilifi and Tharaka districts were extracted with water/methanol yielding twenty-three extracts. The extracts were tested against chloroquine sensitive (NF54) and resistant (ENT30) P. falciparum strains in vitro using (3)Hypoxanthine assay.

RESULTS

Seven (30%) extracts showed activity against P. falciparum with IC(50) values below 20 microg/ml. The remaining 16 extracts showed low or no activity. The most active extracts were from Zanthoxylum chalybeum (Rutaceae) with an IC(50) value of 3.65 microg/ml, Cyperus articulatus (Cyperaceae) with 4.84mug/ml, and Cissampelos pareira (Menispermaceae) with 5.85 microg/ml.

CONCLUSIONS

This study revealed plants, that are potential sources of anti-malarial compounds. Anti-plasmodial activities of extracts of T. simplicifolia, C. pareira, and C. articulatus are reported for the first time.