Abstract

STUDY OF ACTIVE COMPOUNDS OF PLECTRANTHII AMBOINICII LEAVES GROWING IN DALAT CITY, VIETNAM AND ITS ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES

Trinh Tang-Le-Quynh, Ha Ngo-Duy-Tuy, Khang Mai-Thanh, Dinh Tran-Thanh, Trung Tran-Ngoc, Khiet Le-Quang, Bao Nguyen-Quoc, Nhu Doan-Thi-Quynh, Huong Cao-Thi-Thu and Sy Duong-Quy*

ABSTRACT

Plectranthii amboinicii (Lour.) Speng - Lamiaceae (Mexican mint) is a plant used by Vietnamese people for eating and treating some illnesses. This study is designed to quantify the oil content extraction of Folium Plectranthii amboinicii in different regions and seasons in Southern Viet Nam and its antimicrobial and antioxidant properties. Plectranthii amboinicii leaves were harvested in 5 provinces with different climates in the Southern of Vietnam, including Dalat city (Langbiang highland), in March, June, September and December. The extract of Plectranthii amboinicii leaves were quantified for the active compounds and analyzed for antibacterial, antifungal and antioxidant effects. The results of our study showed that Plectranthii amboinicii leaves, harvested from Dalat city, had the highest oil extracted volume in March and lowest in June (1.20 ± 0.06 vs. 0.68 ± 0.03 mL/kg). Among extracted oil compounds, the percentage of p-cymene and carvacrol was highest (23.3% and 55.3%, respectively). There was an inverse relationship between the concentration of p-cymene and carvacrol of Plectranthii amboinicii leaves harvested in Dalat city and other regions. Plectranthii amboinicii leaf oil had antibacterial effects against Staphylococcus aureus, Escherichia coli and Bacillus subtilis and antifungal effect against Candida albicans. In addition, with high concentration, the antioxidant activity of Folium Plectranthii amboinicii was similar to BTH (butyl hydroxyl toluene). The oil compound and medical effect of Folium Plectranthii amboinicii are changed according to geographical areas and harvesting seasons. This plant might be used as a medicine due to its antibacterial and antioxidant effects.

Keywords: Plectranthii amboinicii; oil extract; antibacterial effect; antifungal effect; antioxidant; Dalat city.