BIOACTIVITIES OF THE THAI MEDICINAL AND EDIBLE PLANTS C. CAJAN, M. CITRIFOLIA AND O. AMERICANUM

Objective: Inflammation and oxidative stress are closely related and play a role in various diseases. If an infectious component plays a role, an antibacterial effect is of advantage. Thus, natural remedies which combine different bioactivities have a broader range of application.Methods: Here we elucidate the anti-inflammatory, antioxidant and antibacterial effects of three edible and traditionally used Thai plants including leaves of Cajanus cajan, Morinda citrifolia and Ocimum americanum.Results: The extracts exerted significant anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated macrophages. C. cajan extract shows a broad spectrum of antibacterial activity against Gram positive and negative, aerobic and anaerobic bacteria, whereas M. citrifolia and O. americanum possess antibacterial activity only against anaerobic bacteria. Extracts of all three plants showed significant antioxidant effects.Conclusion: The three plants are potential herbal remedies or supplements for functional food for the treatment and prevention of inflammation, oxidative imbalance, and bacterial infections or associated diseases.Â

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.Â