Pone Kamdem Boniface

Substantiation of the ethnopharmacological use of Conyza sumatrensis (Retz.) E.H.Walker in the treatment of malaria through in-vivo evaluation in Plasmodium berghei infected mice

ETHNOPHARMACOLOGICAL RELEVANCE Scientific validation of ethnopharmacologically used plants and their utilization for therapeutic interventions can be a source of affordable treatment especially for neglected diseases in endemic areas. Conyza sumatrensis is a plant which finds its use in treating malaria like fevers but lacks proper scientific validation. Our study has tried to address this gap by authenticating its traditional use for the treatment of malaria. AIM OF THE STUDY Evaluate the antimalarial activity of extracts derived from Conyza sumatrensis for its ethnopharmacological validation. MATERIALS AND METHODS Shade dried leaves were extracted with varying concentrations of ethanol and concentrated for bio-evaluation. Swiss albino mice infected with 1 × 10(6) parasitized red blood cells, were orally administered with test extracts for 7 days in two sets of experiments. The first set was used to evaluate alcoholic, hydroalcoholic and aqueous extracts while the second set was used to evaluate the dose response of alcoholic extract ranging from 500-1600 mg/kg. Mean survival time, parasitaemia and haemoglobin levels were considered to interpret the antimalarial potential. Phytochemical analysis for the presence of flavonoids, alkaloids tannins, total phenolics, riboflavin and thiamine was also carried out. RESULTS Among the three extracts administered at 1000 mg/kg, chemo suppression was significantly (p<0.001) observed in the alcoholic extract (62.59 ± 12.52%) followed by hydroalcoholic (41.81 ± 19.04%, p<0.01) and aqueous (32.04 ± 19.04%, P<0.05) indicating that the active constituents leach out in ethanol. The dose response study involving the ethanol extract concluded the optimum dose to be 1000 mg/kg, as also evidenced by the haemoglobin levels. CONCLUSION The plant exhibits moderate antimalarial activity which can be further prospected for active fractions or pure molecules for adjunctive therapy.

Bioactivity-guided isolation of antiplasmodial constituents from Conyza sumatrensis (Retz.) E.H. Walker.

Conyza sumatrensis (Retz.) E.H. Walker (Cs) leaves are used for traditional treatment of malaria in Cameroon. However, the antimalarial activity of the leaf constituents of this plant is still unexplored. The aim of our investigation was to evaluate the antiplasmodial activity of some bioactive constituents from Cs leaves. Compounds were isolated from Cs leaves and structurally elucidated using extensive spectroscopic analysis. The in vitro antiplasmodial activity of the extracts and pure compounds were evaluated on chloroquine-sensitive strain (NF54) of Plasmodium falciparum. The in vivo assay was done by administering seven doses of extracts in mice infected with Plasmodium berghei K173 through oral route. Cytotoxicity of pure compounds on murine macrophage cells was performed through [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] (MTT) test. Hemolysis and lactate dehydrogenase assays were also carried out using standard procedures. The in silico prediction of bioactive constituents was performed through Autodock Vina. Polarity-based extracts from Cs were found to be active against P. falciparum (NF54) and P. berghei (K173) in vitro and in vivo respectively. Further, bioactivity-guided isolation of n-hexane fraction yielded three compounds, (1), (2) and (3) with IC50 of 34, 17.9 and 18μg/ml, respectively, while the ethyl acetate fraction afforded the fourth compound with an IC50 of 25μg/ml, indicating anti-malarial potential of Cs through PfLDH interaction without compromising normal cell growth. This study reports for the first time, the antiplasmodial activity of bioactive constituents from Cs and confirms its traditional use.

Current state of knowledge on the traditional uses, phytochemistry, and pharmacology of the genus Hymenaea

ETHNOPHARMACOLOGICAL RELEVANCE Plants of the genus Hymenaea (Fabaceae) are used in South American and Asian traditional medicines to treat a multitude of disorders, like cough, diarrhea, dysentery, intestinal colic, pulmonary weakness, asthma, anemia, sore throat, and for the treatment of kidney problems, viral related disorders, chronic cystitis, bronchitis, and bladder infections. Some Hymenaea species are also used as vermifuge, and for the treatment of arthritis, and inflammation conditions. This review deals with updated information on the traditional uses, phytochemistry and pharmacology of ethnomedicinally important Hymenaea species in order to provide an input for the future research prospects. METHODS Literature available in various recognized databases including Google Scholar, PubMed, SciFinder, Scopus, Springer, Wiley, ACS, Scielo and Web of Science, as well as from theses, dissertations, books, reports, and other relevant websites (www.theplantlist.org), are surveyed, analysed, and included in this review. Herein, the literature related to chemical constituents and pharmacological activities were searched in November 2016. RESULTS The literature provided information on ethnopharmacological uses of the South American and African species of the genus Hymenaea (e.g., H. courbaril, H. stigonocarpa, H. onblogifolia, H. martiana, H. parvifolia (South America) and H. verrucosa (African species)) for the treatment of multi-factorial diseases. From these plant species, more than 130 compounds, including fatty acids, flavonoids, terpenoids and steroids, phthalides, phenolic acids, procyanidins and coumarins were identified. Experimental evidences confirmed that the Hymenaea spp. could be used in treating inflammatory disorders, asthma, diarrhea, and some microbial infections. However, reports on the toxicity of Hymenaea species remain scarce. CONCLUSION Plants of this genus have offered bioactive samples, both from crude extracts and pure compounds, thus substantiating their effectiveness in traditional medicine. However, intensive investigations of all the species of Hymenaea spp. relating to phytochemical and pharmacological properties, especially their mechanism of action, safety and efficacy could be the future introspection.

Acute and sub-chronic toxicity of HPLC fingerprinted extract of Conyza sumatrensis (Retz.) E.H. Walker in rodents

ETHNOPHARMACOLOGICAL RELEVANCE Conyza sumatrensis (CS) is an extensively used medicinal herb in the tropics for varied ailments related to pain, inflammation and malaria. Though in constant folkloric use, scientific validations are proving valuable. AIM OF THE STUDY Evaluate the safety profile of methanol extract from CS in mice and rats through acute and sub-chronic toxicity studies respectively. MATERIAL AND METHODS Acute toxicity study involved the single oral administration of CS at 1000, 2000 and 3000mg/kg in mice, while the sub chronic toxicity was carried upon in rats at doses 250, 500 and 1000mg/kg/day for 28 days. Besides body weight, general behaviour and mortality, serum biochemical parameters and liver histology were assessed after 7 and 28 days for acute and sub-chronic study respectively. The parameters were again checked on days 14 and 56 in order to assess the recovery from damage, if any. HPLC fingerprinting of the aqueous and methanol extract was performed through C18 column using water: acetonitrile as mobile phase with observations at 240nm. RESULTS In the acute toxicity test, single oral dose of 1000, 2000 and 3000mg/kg of CS did not result in any behavioural changes or mortality, indicating non toxicity. In sub-chronic toxicity studies in rats, no mortality was observed at 250, 500 and 1000mg/kg/day when administered orally for a period of 28 days. Except Serum Glutamate Pyruvate Transaminase (SGPT) level in acute study and Alkaline Phosphatase (ALP), SGPT and Serum Glutamate Oxaloacetate Transaminase (SGOT) level in sub-chronic study, all the observational, haematological and biochemical parameters studied showed non-significant changes. Histological examination of liver did not reveal any treatment-related effects in any of the studies. Moreover, haematological and biochemical changes orchestrated by CS got normalised after 14 and 56 days post-treatment in acute and sub-chronic toxicity respectively. The HPLC fingerprint could resolve 11 and 28 peaks from aqueous and methanol extracts respectively. CONCLUSION The experiments indicate the methanol extract to be safe even at high and repeated doses in pre-clinical studies even though the constituents are more than in aqueous extract.

RP-HPLC-DAD method for the identification of two potential antioxidant agents namely verminoside and 1-O-(E)-caffeoyl-β-gentiobiose from Spathodea campanulata leaves

A simple and reliable high-performance liquid chromatographic method was successfully developed for the study of fingerprint chromatograms of extract and fractions from the leaves of Spathodea campanulata (SC) using verminoside (1) and 1-O-(E)-caffeoyl-β-gentiobiose (2) as marker compounds. Antioxidant activity of SC was determined by using free radical of 2,2-diphenyl-1-picryl-hydrazyl-hydrate as an experimental model. The docking study of selected target, tyrosinase and ligands (ascorbic acid, compounds 1 and 2) was performed through Autodock Vina v0.8. Fingerprints of methanol, chloroform, ethylacetate, n-butanol and water extracts could resolve 13, 11, 22, 16 and 5 peaks, respectively. Extract, fractions and compounds 1 and 2 previously isolated from SC displayed remarkable antioxidant activity with radical-scavenging activity ranging from 2.5 to 6.7 μg/mL. In silico study identified compounds 1 and 2 as potential inhibitors of tyrosinase correlating with the observed antioxidant activity in vitro.

Membrane stabilisation: a possible anti-inflammatory mechanism for the extracts and compounds from Spathodea campanulata

This study was undertaken to evaluate the efficiency of extract, fractions and pure molecules from Spathodea campanulata (SC) towards inflammation. Polarity-based extracts of SC were found active in stabilising red blood cell (RBC) membrane indicating anti-inflammatory potential. Bioactivity-guided isolation of SC produced 1-O-(E)-caffeoyl-β-gentiobiose and (2S)-1,2-di-O-[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-O-[α-d-galctopyranosyl-(1″ → 6′)-O-β-d-galactopyranosyl] glycerol as the active constituents with 65.91% and 67.41% of membrane stability, respectively. Activity of the third compound (verminoside) could not be ascertained owing to extremely low recoverability. Furthermore, the isolated compounds were subjected to in silico studies. The compounds showed good binding affinity towards cyclooxygenase-2. Absorption, distribution, metabolism & excretion (ADME)-toxicity studies illustrated that the isolated compounds are free of toxicity. These observations help us to conclude that SC might exert its anti-inflammatory activity by soothing the RBC membrane as it is the case for non-steroidal anti-inflammatory drugs towards lysozomal membranes. Therefore, SC might be considered as a potential candidate for development of anti-inflammatory drugs.