In vitro antibacterial, antioxidant, total phenolic contents and anti-HIV-1 reverse transcriptase activities of extracts of seven Phyllanthus sp

AbstractPhyllanthus species has long been used in folk medicine in many countries as antimicrobials and/or antioxidants. Eighty percent methanol extracts obtained from seven Phyllanthus sp. were evaluated for antibacterial activity using the broth micro-dilution assay, anti-HIV-1 reverse transcriptase (RT) activity using the HIV-RT assay, antiradical scavenging effects and phenolic contents using the DPPH assay and Folin–Ciocalteau colorimetric method, respectively. Best antibacterial activity as indicated by the minimum inhibitory concentration (MIC) values was obtained by Phyllanthus amarus against Staphylococcus aureus (Gram-positive) with a MIC value of 17.7μg/ml. Phyllanthus myrtifolius and Phyllanthus urinaria inhibited growth of Pseudomonas stutzeri (Gram-negative) with MIC values of 78μg/ml and 117μg/ml, respectively. A strong inhibition of HIV-RT was obtained by Phyllanthus pulcher (IC50 5.9μg/ml) followed by P. urinaria and P. myrtifolius (IC50 of 10.4 and 12.7μg/ml, respectively). A remarkable DPPH scavenging effect was observed with P. myrtifolius, Phyllanthus reticulatus and P. urinaria (IC50 of 10.2, 10.8 and 17.4μg/ml, respectively). Highest total phenolic contents were recorded for P. myrtifolius and P. urinaria (207 and 205mg/GAE/g respectively). With the exception of P. amarus, Phyllantus debilis and P. pulcher, total phenolic contents correlated with DPPH radical scavenging activity. Our findings support the uses of the Phyllanthus species in traditional medicine. The interesting biological activities obtained by P. myrtifolius, P. urinaria and P. pulcher need to be further investigated to isolate active agents and to study their mechanism of action

Cyclooxygenase inhibition and antimycobacterial effects of extracts from Sudanese medicinal plants

AbstractFifty one dichloromethane, ethyl acetate and ethanol extracts obtained from seven tree species used in Sudanese traditional medicine were screened for in vitro anti-inflammatory activity using COX-1 and COX-2 assays and for antimycobacterial activity using the broth micro-dilution methods against Mycobacterium aurum A+. In the cyclooxygenase assays, all ethyl acetate (leaf, bark, root) and ethanol root extracts of Acacia seyal, ethyl acetate twig extracts of Capparis decidua, dichloromethane bark extracts of Combretum hartmannianum and ethanol bark extracts of Ziziphus spina-christi showed inhibitory effect against prostaglandin synthesis by COX-2 ranging from 58 to 97% and weak (<50%) or no activity against COX-1 induced prostaglandin production. In the antimycobacterial assays, ethanol extracts of A. seyal (bark), C. hartmannianum (leaf, bark), Kigelia africana (bark) and Z. spina-christi (bark) inhibited growth of M. aurum A+ with MIC values ranging between 0.19 and 1.56 mg/ml. The in vitro anti-inflammatory activity observed in this study support the utilization of these plants in Sudanese traditional medicine as crude anti-inflammatory agents. The inhibition of COX-1 and COX-2 and the antimycobacterial effects of these plants have not been reported previously. Isolation of bioactive compounds from A. seyal and Erythrina latissima are in progress in our laboratory

In vitro pharmacological investigation of extracts from some trees used in Sudanese traditional medicine

AbstractExtracts obtained from seven tree species used in Sudanese traditional medicine were screened for antibacterial, anti-cholinesterase activities and investigated for potential mutagenic effects using the Ames test. Antibacterial activity was detected using the micro-dilution assay. The extracts were tested against Gram-positive: Bacillus subtilis and Staphylococcus aureus and Gram-negative: Escherichia coli and Klebsiella pneumoniae. Of the plant extracts investigated, 75% showed minimum inhibitory concentration (MIC) values less than/or around 1.5 mg/ml. Extracts obtained from Acacia seyal (ethanolic leaf extract) and Combretum hartmannianum (ethanolic leaf and root extracts), inhibited bacterial growth of both Gram-positive and Gram-negative bacteria at a concentration less than/or around 0.39 mg/ml. The lowest MIC value (less than/or around 0.1 mg/ml) was observed with the ethanolic (leaf, bark and root) and dichloromethane (bark) extracts of A. seyal, dichloromethane root extract of Capparis decidua, ethyl acetate (bark and root) and ethanolic (root) extracts of Erythrina latissima against Gram-negative bacteria Klebsiella pneumoniae. In the acetylcholinesterase inhibitory test, 58% of the plant extracts were active at a concentration of/or below 1 mg/ml using the micro-dilution assay. The lowest IC50 value was 0.09 mg/ml observed with the ethanolic bark and root extracts of E. latissima and Kigelia africana. No potential mutagenic effects was shown by the investigated plant extracts in the Ames assay