Antimicrobial activity of medicinal plants against oral microorganisms

Ethanol extracts of eight plant species used traditionally in South Africa for the treatment of oral diseases were investigated for in vitro antimicrobial activity against oral pathogens namely Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Actinomyces israelii, Candida albicans, Porphyromonus gingivalis, Privotella intermedia and Streptococcus mutans using the disk diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using micro dilution. The cytotoxicity and therapeutic index (TI) of selected active extracts were also determined. Out of eight plants, six (Annona senegalensis, Englerophytum magalismontanum, Dicerocarym senecioides, Euclea divinorum, Euclea natalensis, Solanum panduriforme and Parinari curatellifolia) exhibited MIC values ranging from 25.0 mg/ml to 0.8 mg/ml. Gram negative bacteria were found to be more resistant to the plant extracts than Gram positive bacteria, except for Euclea natalensis which inhibited all three Gram negative bacteria tested in this study. All plant extracts showed moderate cytotoxicity on the Vero cell line. The fifty percent inhibitory concentration (IC(50)) of all plants tested range from 92.3 to 285.1 microg/ml.

In vitro anti-HIV-1 properties of ethnobotanically selected South African plants used in the treatment of sexually transmitted diseases

ETHNOPHARMACOLOGICAL RELEVANCE

[corrected The plants selected in this study are used traditionally in the treatment of sexually transmitted diseases and traditional healers interviewed claimed these plants can also help AIDS patients.

AIM

To evaluating the in vitro anti-HIV properties of selected plants in various bioassays.

MATERIALS AND METHODS

The extracts were evaluated for their inhibition against alpha-glycohydrolase, reverse transcriptase and viral proteins (NF-kappaB and Tat) which play a significant role in the HIV life cycle.

RESULTS

Terminalia sericea extract (IC(50)=92mg/ml) exhibited a considerable alpha-glucosidase inhibitory activity which was better than acarbose (IC(50)=131mg/ml) under our assay conditions. In the reverse transcriptase assay, T. sericea also showed good inhibitory activity (IC(50)=43mg/ml), which was higher than that of the reference drug, Adriamycin (IC(50)=100mg/ml). The ethyl acetate extract of Elaeodendron transvaalense exhibited the most potent inhibitory activity in both the NF-kappaB and Tat assays with inhibitory activity of 76% and 75% respectively at a concentration of 15mg/ml. The acetone and chloroform extracts of E. transvaalense and Zanthoxylum davyi also showed good activity in the NF-kappaB and Tat assays.

Antimicrobial activity, toxicity and the isolation of a bioactive compound from plants used to treat sexually transmitted diseases

Extracts of six ethnobotanically selected medicinal plants (Anredera cordifolia, Elaeodendron transvaalense, Elephantorrhiza burkei, Senna petersiana, Terminalia sericea and Rauvolfia caffra) used traditionally to treat sexually transmitted diseases (STD's) were investigated for antibacterial activity using the agar dilution method. Of the six collected, Terminalia sericea, Senna petersiana and Anredera cordifolia were also investigated for cytotoxicity. The phytochemical studies on Senna petersiana resulted in the isolation of luteolin, which also showed antimicrobial activity. Only the Senna petersiana extract and luteolin isolated from it were tested for antiviral activity and showed some activity at the highest non-toxic concentration of 24 and 500 microg/ml, respectively. The results of the antimicrobial screening support the ethnomedicinal uses of these plants to some extent.