In vitro biological activities of selected medicinal plants and their synergistic effects.

The present work aimed to use the methanol extracts of Croton bonplandianus (Cb) and Tithonia diversifolia (Td) and the synergistic activity of Croton bonplandianus and Tithonia diversifolia (CbTd) for the phytochemical screening, anti-microbial, anti-oxidant and anti-inflammatory activities. Phytochemical screening was done by the standard protocols. In vitro antimicrobial, antioxidant and anti-inflammation, were assayed by using disc diffusion, total antioxidant activity, DPPH method, HRBC (human red blood cells) membrane stabilization and anti-protein denaturation tests. The synergistic approach of the two plants showed potent antimicrobial, antioxidant and anti-inflammation activity. In vitro antibacterial activity was done against Pseudomonas aeroginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus at different concentrations. The maximum zone of inhibition (21 mm) was observed in the combinatorial approach. The maximum inhibition of free radicals is observed in CbTd with a low IC₅₀, i.e., 7.64 mg/ml, followed by Cb with an IC₅₀ value of 11.8mg/ml and Td with an IC₅₀ of 28.3 mg/ml. The percentage inhibition of hemolysis and protein denaturation is high in CbTd (93% and 69%). The experimental analysis reveals the effectiveness of the synergistic effect of these plants with anti-microbial, anti-oxidant and anti-inflammatory activity, further it can be used in the formulations against infectious human pathogens.