Radical scavenging compounds from the aerial parts of Solenostemon monostachys briq (Lamiaceae)

Background: Solenostemon monostachys Briq. (Lamiaceae) is a weed widely used in ethno medicine to treat infections and inflammatory conditions but the active compounds are yet to be identified. This study isolated and identified the radical scavenging compounds from S. monostachys crude extract using diphenyl-1, 1-picryl hydrazyl (DPPH) to monitor the separation.Materials and Methods: The crude extract of the aerial parts of the plant was evaluated for antimicrobial activity using the agar diffusion test, anti-inflammatory test using carrageenan induced oedema of the rat paw and radical scavenging test using diphenyl-1, 1-picryl hydrazyl (DPPH). Repeated chromatographic separation of the ethyl acetate and n-butanol fractions on silica gel and Sephadex LH-20, monitored by DPPH bio-autographic assay resulted in the isolation of seven active compounds, which were identified using spectroscopic methods and comparison with literature data.Results: The ethyl acetate and n-butanol fractions were the most active fractions and contained apigenin, apigenin glucuronide, luteolin, caffeic acid, methyl caffeate, rosmarinic acid and methyl rosmarinate as the radical scavenging compounds with EC50 values of 26.67 ± 0.31, 185.89 ± 1.02, 5.35 ± 0.31, 3.92 ± 0.06, 13.41 ± 0.18, 4.99 ± 0.10, 5.97 ± 0.08 μg/ml respectively compared with 2.32 ± 0.08 μg/ml for quercetin as the reference standard.Conclusion: The isolated compounds are reported for the first time in this plant. The presence of the compounds in S. monostachys P. Beauv. (Briq.) (Lamiaceae) may provide justification for some of the ethnomedicinal uses of the plant in infections and inflammatory conditions.Keywords: Flavonoids, caffeic acid derivatives, radical scavenging ability, Lamiacea

RADICAL SCAVENGING COMPOUNDS FROM THE AERIAL PARTS OF SOLENOSTEMON MONOSTACHYS BRIQ (LAMIACEAE)

Background: Solenostemon monostachys Briq. (Lamiaceae) is a weed widely used in ethno-medicine to treat infections and inflammatory conditions but the active compounds are yet to be identified. This study isolated and identified the radical scavenging compounds from S. monostachys crude extract using diphenyl-1, 1-picryl hydrazyl (DPPH) to monitor the separation. Materials and Methods: The crude extract of the aerial parts of the plant was evaluated for antimicrobial activity using the agar diffusion test, anti-inflammatory test using carrageenan induced oedema of the rat paw and radical scavenging test using diphenyl-1, 1-picryl hydrazyl (DPPH). Repeated chromatographic separation of the ethyl acetate and n-butanol fractions on silica gel and Sephadex LH-20, monitored by DPPH bio-autographic assay resulted in the isolation of seven active compounds, which were identified using spectroscopic methods and comparison with literature data. Results: The ethyl acetate and n-butanol fractions were the most active fractions and contained apigenin, apigenin glucuronide, luteolin, caffeic acid, methyl caffeate, rosmarinic acid and methyl rosmarinate as the radical scavenging compounds with EC50 values of 26.67 ± 0.31, 185.89 ± 1.02, 5.35 ± 0.31, 3.92 ± 0.06, 13.41 ± 0.18, 4.99 ± 0.10, 5.97 ± 0.08 μg/ml respectively compared with 2.32 ± 0.08 μg/ml for quercetin as the reference standard. Conclusion: The isolated compounds are reported for the first time in this plant. The presence of the compounds in S. monostachys P. Beauv. (Briq.) (Lamiaceae) may provide justification for some of the ethnomedicinal uses of the plant in infections and inflammatory conditions

ISOLATION AND CHARACTERIZATION OF CHEMICAL CONSTITUENTS FROM Chrysophyllum albidum G. DON-HOLL. STEM-BARK EXTRACTS AND THEIR ANTIOXIDANT AND ANTIBACTERIAL PROPERTIES

Background: The plant, Chrysophyllum albidum is indigenous to Nigeria and its stem-bark has found relevance in folkloric medicine for infections and oxidative stress linked diseases medicaments. The study targets to isolate the chemical constituents accountable for the antioxidant and antibacterial actions of the plant stem-bark to substantiate some of its ethnomedicinal uses. Materials and Methods: Stem-bark extract of Chrysophyllum albidum was obtained from 80 % ethanol was partitioned in sequence with ethyl acetate (EtOAc) and n-butanol. The solvent fractions and isolated compounds were verified for antioxidant chattels utilizing 2-2-diphenyl-1-picrylhydrazyl. Antibacterial actions were also assessed by agency of agar-diffusion and broth micro dilution methods. EtOAc fraction was on many occasions chromatographed on silica and Sephadex LH-20 column to afford four compounds and their chemical structures were proven with the employment of NMR (1D and 2D) and MS. Results: Chromatographic fractionation of EtOAc fraction with the premier antioxidant and antimicrobial activities afforded stigmasterol (1), epicatechin (2), epigallocatechin (3) and procyanidin B5 (4). Procyanidin B5 isolated for the first time from Chrysophyllum genus proven the supreme antioxidant activity with IC50 values of 8.8 µM and 11.20 µM in DPPH and nitric oxide assays respectively and equally established the ultmost inhibitory activity against Escherichia coli (MIC 156.25 μg/mL), Staphylococcus aureus (MIC 156.25 μg/mL), Pseudomonas aeruginosa (MIC 625 μg/mL) and Bacillus subtilis (MIC 156.25 μg/mL). Conclusion: The antibacterial and antioxidant activities of epicatechin, epigallocatechin and procyanidin B5 isolated from Chrysophyllum albidum stem-bark substantiate the folkloric use

Screening of the Pan-African Natural Product Library Identifies Ixoratannin A-2 and Boldine as Novel HIV-1 Inhibitors

The continued burden of HIV in resource-limited regions such as parts of sub-Saharan Africa, combined with adverse effects and potential risks of resistance to existing antiretroviral therapies, emphasize the need to identify new HIV inhibitors. Here we performed a virtual screen of molecules from the pan-African Natural Product Library, the largest collection of medicinal plant-derived pure compounds on the African continent. We identified eight molecules with structural similarity to reported interactors of Vpu, an HIV-1 accessory protein with reported ion channel activity. Using in vitro HIV-1 replication assays with a CD4+ T cell line and peripheral blood mononuclear cells, we confirmed antiviral activity and minimal cytotoxicity for two compounds, ixoratannin A-2 and boldine. Notably, ixoratannin A-2 retained inhibitory activity against recombinant HIV-1 strains encoding patient-derived mutations that confer resistance to protease, non-nucleoside reverse transcriptase, or integrase inhibitors. Moreover, ixoratannin A-2 was less effective at inhibiting replication of HIV-1 lacking Vpu, supporting this protein as a possible direct or indirect target. In contrast, boldine was less effective against a protease inhibitor-resistant HIV-1 strain. Both ixoratannin A-2 and boldine also inhibited in vitro replication of hepatitis C virus (HCV). However, BIT-225, a previously-reported Vpu inhibitor, demonstrated antiviral activity but also cytotoxicity in HIV-1 and HCV replication assays. Our work identifies pure compounds derived from African plants with potential novel activities against viruses that disproportionately afflict resource-limited regions of the world

ANTIMICROBIAL AGENTS FROM SOME NIGERIAN PLANTS

Amongst Nigerian plants with bioactivity are Piliostigma and Mitracarpus species. Ethyl acetate fraction of Piliostigma thonnigii contains C-methylflavonols as compounds responsible for both the antibacterial and anti-inflammatory activities of the leaves. Mitracarpus scaber has naphthoquinones known to possess a wide range of biological actions including antibacterial and antifungal activities. Key Words: Piliostigma thonningii, Piliostigma reticulatum, Mitracarpus scaber, Staphylococcus aureus, Candida pseudotropicalis, Antibacterial and anti-inflammatory activities. Nig. J. Nat Prod. And Med. Vol.3 1999: 26-2

ANTI-INFLAMMATORY ACTIVITY OF SELECTED NIGERIAN MEDICINAL PLANTS

Extracts of nineteen plant species from an inventory of Nigerian medicinal plants were screened for activity in two in vitro anti-inflammatory model test systems, inhibition of prostaglandin biosynthesis and PAF-induced elastase release from neutrophilis. Anacardium occidentale and Acalipha hispida were active in both test systems. Amatranthus spinosus had high specific prostaglandin synthesis inhibitory activity, while Bryophyllum pinnatum and Combretodendron macrocarpum had specific activity in the PAF elastase release test. The results obtained were related to the traditional uses of the plants and chemical constituents where known. Key Words: Nigerian medicinal plants; anti-inflammatory activity, prostaglandin biosynthesis; PAF-induced elastase release Nig. J. Nat. Prod. And Med. Vol.1 1997: 10-1

Hypotensive Activity of the Ethanol Extract of \u3cem\u3ePavetta crassipes\u3c/em\u3e Leaves

Pavetta crassipes leaf is routinely used locally in Nigeria for the management of respiratory disorders and hypertension. The hypotensive and other cardiovascular effects of Pavetta crassipes were investigated in cats and rats. The effects of the extract on rat and cat blood pressures, isolated rat atria, rat portal vein, isolated rat aorta and rat vas deferens were studied. Specific receptor antagonists (atropine, mepyramine, phentolamine, propranolol) were used to elucidate the underlying mechanism(s) involved in the cardiovascular changes induced by P. crassipes. The results revealed that the ethanolic extract of Pavetta crassipeslowered the blood pressures of cats and rats in a dose dependent manner. The extract also caused a concentration-dependent decrease in the force of contraction of the isolated rat atria and rat portal vein. The decreases in blood pressure values were attenuated in the presence of a β-adrenoceptor antagonist, propranolol. The extract also attenuated isoprenaline-induced contraction of the rat atria. However, the extract did not affect contractions evoked by KCl, norepinephrine and 5-HT on the rat aorta. Pavetta crassipescontains biologically active substances that may be useful in the management of hypertension