ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF EMBLICA EXTRACTS OBTAINED BY SUPERCRITICAL CARBON DIOXIDE EXTRACTION AND METHANOL EXTRACTION

ABSTRACT

This study is aimed to evaluate the antimicrobial and antioxidant activities of two extracts of emblica (Phyllanthus emblica L.) obtained by supercritical fluid extraction (SFE) and methanol extraction. The SFE extract showed strong antimicrobial activity against all microorganisms tested, whereas the methanolic extract showed low activity against Staphylococcus aureus and fungi. In contrast, the methanolic extract exhibited significantly higher antioxidant activity than the SFE extract. The SFE extract was analyzed by gas chromatography with mass spectrometric detector. Thirty compounds were tentatively identified, representing 99.67% of the volatile components. β‐Bourbonene, teracosane, palmitic acid, thymol, β‐caryophyllene and undecane were the major compounds. The methanolic extract was subjected to separation and purification using reverse‐phase high‐performance liquid chromatography. Kaempferol 3‐β‐D‐glucopyranoside (1), kaempferol (2), quercetin (3), isocorilagin (4) and geraniin (5) respectively, were identified by spectral methods, ¹H and ¹³C nuclear magnetic resonance spectroscopy, ultraviolet‐visible spectrophotometry and mass spectroscopy, and comparison with literatures.

PRACTICAL APPLICATIONS

The study can be considered as the first report on the in vitro antimicrobial and antioxidant properties of supercritical fluid extraction (SFE) and methanolic extracts prepared from Phyllanthus emblica. The results introduce a unique natural source that possesses strong antimicrobial and antioxidant substances. The SFE extract had a strong and broad spectrum of antimicrobial activity, and in some cases, even found to have similar activity to the antibiotics ampicillin and nystatin. On the other hand, the methanolic extract exhibited quite strong antioxidant activities, which were found to be similar, and in some cases even higher than the reference compound butylated hydroxytoluene (BHT). Hence, the extracts of P. emblica could be used as a natural preservative ingredient in food and/or pharmaceutical industry.