Abstract
Orthosiphon stamineus is considered an important traditional folk medicine. In this study ethanol and aqueous extracts of O. stamineus were evaluated in vitro for their antioxidant, antimicrobial as well as for their immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). The DPPH radical scavenging method was used for the determination of antioxidant activity, while the antibacterial efficacy was investigated by both disc diffusion method and Minimum Inhibitory Concentration (MIC) against four bacterial strains (Gram-positive and Gram-negative). Furthermore, the immunomodulatory potential of the extracts was investigated through the MTT assay. Aqueous extract of O. stamineus exhibited significant free radical scavenging activity with IC50 9.6 µg/mL, whereas the IC50 for the ethanol extract was 21.4 µg/mL. The best antimicrobial activity was shown by the aqueous extract of O. stamineus against Staphylococcus aureus, with inhibition zone of 10.5 mm and MIC value 1.56 mg/mL. Moreover, the results observed from the MTT assay showed that both plant extracts stimulated the PBMCs proliferation in vitro in a concentration-dependent manner, but the aqueous extract has remarkable activity against PBMCs. These findings indicate that O. stamineus showed high antioxidant activity and may be considered as an immunomodulatory agent.
Highlights
Medicinal plants are widely used all over the World as folk medicine for several purposes
This study was performed on ethanol and aqueous extracts of O. stamineus to determine their antioxidant activity by measuring the DPPH radical scavenging activity, and to investigate the in vitro antibacterial activity by the disc-diffusion and Minimum Inhibitory Concentration (MIC) methods, as well as to assess the stimulation effects against human peripheral blood mononuclear cells (PBMCs)
It was shown that both extracts of O. stamineus exhibited antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Streptococcus agalactiae) but not Gram-negative bacteria (Escherichia coli and Klebsilla pneumonia)
Summary
Medicinal plants are widely used all over the World as folk medicine for several purposes. Reactive oxygen species (ROS) and other free radicals are responsible for many diseases, such as arteriosclerosis, heart diseases, aging process and cancer [2] The free radicals such as ROS, including hydroxyl radicals, superoxide anions, and hydrogen peroxide, play an important role in promoting tissue damage in living organisms. They may lead to cell damage through membrane lipid peroxidation and DNA mutations and as a consequence of that many diseases such as cancer may develop. This study was performed on ethanol and aqueous extracts of O. stamineus to determine their antioxidant activity by measuring the DPPH radical scavenging activity, and to investigate the in vitro antibacterial activity by the disc-diffusion and MIC methods, as well as to assess the stimulation effects against human PBMCs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
