Anti-inflammatory, antibacterial, and antioxidant activities of Thai medicinal plants.

Objective: Acacia farnesiana (L.) Willd, Senna alata (L.) Roxb., Sesbania grandiflora (L.) Pers., Syzygium cumini (L.) Skeels and Tabernaemontana divaricate (L.) R. Br. ex Roem. & Schult. are used in Thai traditional remedies to treat various disorders ranging from fever and pain to inflammation or microbial infections. However, there is a lack of scientific data on some of the biological activities. Methods: The present study was designed to compare the antibacterial, antioxidant, and anti-inflammatory effects of the five plants. Ethanolic extracts of A. farnesiana, S. alata, S. grandiflora, S. cumini, T. divaricata were firstly compared for antioxidant activity using free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power tests. Antibacterial activity indicated by minimum bactericidal concentration (MBC) was determined using broth and agar dilution tests against aerobic and anaerobic pathogenic bacterial strains. The anti-inflammatory activity was evaluated in vitro using a lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage model. Results: All the tested extracts exerted antioxidant, antibacterial and anti-inflammatory effects. S. cumini and S. grandiflora extracts showed the highest free radical scavenging activities. S. cumini extract showed the highest activity against Staphylococcus aureus, S. epidermidis, and Corynebacterium diphtheriae. All extracts exerted anti-inflammatory activity as indicated by a reduction of interleukin (IL)-6 secretion and/or tumor necrosis factor (TNF)-α production. Conclusion: Taken together, these findings suggest that the tested plants can be developed as effective herbal remedies for the treatment and prevention of inflammation or associated diseases as well as against bacterial infections. © 2015, International Journal of Pharmacy and Pharmaceutical Science.