Initial evaluation of antioxidant and antibacterial activities of several medicinal plant extracts collected in Vietnam

The diversity of medicinal plants in Vietnam is a rich source to develop novel health products. In this study, the antioxidant and antimicrobial activities of ethanolic extracts of Pluchea indica, Drynaria fortunei, Stephania glabra, lemongrass (Cymbopogon citratus) and lime (Citrus aurantifolia) mixture, and ginger (Zingiber officinale) and kumquat (Citrus japonica) mixture, were evaluated.
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Initial evaluation of antioxidant and antibacterial activities of several medicinal plant extracts collected in Vietnam VNU Journal of Science: Natural Sciences and Technology, Vol. 37, No. 3 (2021) 50-56 Original Article Initial Evaluation of Antioxidant and Antibacterial Activities of Several Medicinal Plant Extracts Collected in VietnamLe Tuan Anh1, Pham Thi Thanh Hang1, Nguyen Thi Bich Loan1,2, Le Quynh Mai1,* 1 VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam 2 Laboratory of Therapeutical Chemistry and Pharmacognosy, Université de Mons, Mons, Belgium Received 11 August 2021 Revised 23 August 2021; Accepted 31 August 2021 Abstract: The diversity of medicinal plants in Vietnam is a rich source to develop novel health products. In this study, the antioxidant and antimicrobial activities of ethanolic extracts of Pluchea indica, Drynaria fortunei, Stephania glabra, lemongrass (Cymbopogon citratus) and lime (Citrus aurantifolia) mixture, and ginger (Zingiber officinale) and kumquat (Citrus japonica) mixture, were evaluated. The extract of ginger and kumquat mixture exhibited the highest free radical scavenging activity (85%), followed by P. indica and S. glabra (60% and 53%, respectively) at the concentration of 0.1 mg/ml. Moreover, the agar well diffusion assay revealed that the extract of S. glabra and the extract of ginger and kumquat mixture were effective in inhibition against Bacillus cereus, Staphylococcus aureus, and Vibrio parahaemolyticus. Especially, the extract of S. glabra at the concentration of 100 mg/ml showed the highest inhibition zone diameter (13±1.73 mm) against B. cereus, which was significantly larger than that of Ceftriaxone (5 g/ml) and other extracts. Keywords: Medicinal plant, antioxidant, free radical scavenging, antibacterial activity.1. Introduction* resistance. For example, Staphylococcus aureus is resistant to many common antibiotics, Plants contain a wide range of natural including penicillin, methicillin and oxacillinbioactive compounds that are good for human [3]. In addition, foodborne pathogens, Bacillushealth due to their antioxidant and antibacterial cereus and Vibrio parahaemolyticus areactivities [1, 2]. Various plants have been used resistant to several antibiotics [4, 5]. Therefore,as traditional medicines in different countries plant materials can be a supplement or anfor bacterial infection treatments. Although alternative therapy for conventional antibiotics.antibiotics are the most effective in treatment of Medicinal plants in Vietnam are diverse andbacterial infections, other solutions should be can be a potential source to develop healthdeveloped because of the increase in antibiotic products [1]. In fact, the Vietnamese people_______ have a long tradition of using a variety of* Corresponding author. E-mail address: lequynhmai80@gmail.com medicinal plants as decoction as well as tea and medicinal liquor. For instance, plants such as https://doi.org/10.25073/2588-1140/vnunst.5306 50 L. T. Anh et al. / VNU Journal of Science: Natural Sciences and Technology, Vol. 37, No. 3 (2021) 50-56 51Pluchea indica, Drynaria fortunei, Stephania 2.2. Preparation of Plant Extractsglabra, are components of many traditional Dried powder of plants (20 g) was extractedremedies and health care products [2]. Some with 200 ml ethanol for 24 hours in a flask, on acommonly used spices such as ginger shaker at room temperature, followed by(Zingiber officinale), lime (Citrus aurantifolia), filtration through filter paper. The extractionkumquat (Citrus japonica) and lemongrass step was repeated 3 times. The combined(Cymbopogon citratus) have been used to treat extracts were concentrated by vacuum rotarycoughs, sore throats, colds and stomachaches evaporator (RE300 Bibby Stuart) to obtain dry[2]. Several studies have evaluated biological extracts. Dry extracts were dissolved inactivity of these spices but there are few study dimethyl sulfoxide (DMSO) 100% to obtain aon their mixtures although they have often been proper test concentration.used in combination. In the present study, the antioxidant and 2.3. Bacterial Strainsantimicrobial potential of ethanolic extracts of Three strains of bacteria, namely BacillusP. indica, D. fortunei, S. glabra, the mixture of cereus, Staphylococcus aureus and Vibriolemongrass and lime, and the mixture of ginger parahaemolyticus preserved at -20 oC wereand kumquat, were investigated. provided by the Department of Microbiology, ...