Anti-bacterial and anti-tyrosinase activities of the methanolic extract from leaves of Tectona grandisPhonmaKham

Anti-bacterial and anti-tyrosinase activities of the methanolic extract from leaves of Tectona grandisPhonmaKham, J.1 and Poeaim, S.1*
1Department of Biology, faculty of Science, King Mongkut’s Institute of Technology Ladkrabang (KMITL), Ladkrabang, Bangkok 10520, Thailand
PhonmaKham, J. and Poeaim, S. (2018). Anti-bacterial and anti-tyrosinase activities of the methanolic extract from leaves of Tectona grandis. International Journal of Agricultural Technology x(x): xxx-xxx.

Abstract: The purpose of this study was compared fresh and fallen Tectona grandis (Teak) leaves for anti-bacterial and anti-tyrosinase activities of methanolic extract. Fresh and fallen teak leaves were collected from Thongphaphum and Phitsanulok silviculture research station. Anti-bacterial activity was determined by disc diffusion method with concentration at 500 µg/disc. Fallen teak leaves extract was showed good activity against Staphylococcus epidermidis and Staphylococcus aureus better than fresh teak leaves. In other hand, fresh teak leaves inhibited growth of Propionibacterium acnes better than fallen teak leaves. The anti-tyrosinase activity was determined by dopachrome method which their activities were lower than ascorbic acid.

Keywords: Anti-bacterial, Anti-tyrosinase, Tectona grandis, Teak
Introduction
The plant has been used as a medicine for a long time and research to apply effectively for products developed with natural ingredients. Tectona grandis or Teak is a plant in the verbenaceae family found most in India, South-East Asian countries. Extracts from different parts of T. grandis can be used the medical property activity as hair growth activity, anti-oxidant activity, cytotoxic anti- inflammatory, anti-hyperglycemic and diuretic (Ramesh and Mahalakshmi, 2014).
The literature review found that methanol extracts from leaves with tetracycline and essential oils had antibacterial activity. (Purushotham et al., 2010; Aboaba et al., 2013). In addition, several researchers have reported the anti-oxidant activity from leaves extract of T. grandis (Senthilkumar et al., 2013; Kushwah et al., 2014).
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1*Coressponding Author: Poeaim, S.; E-mail address: [email protected] and anti-tyrosinase activity an indicator for anti-melanin. Tyrosinase is an important enzyme and production of melanin. This enzyme responsible for colour change brown (Sun et al., 2017; Haliloglu et al., 2017). However, there is no information available on the anti-tyrosinase. While most of the literature in fresh leaves extract this paper intend to fallen teak leaves extract. The purpose of this study was compared fresh and fallen T. grandis (Teak) leaves for anti-bacterial and anti-tyrosinase activities of methanolic extract fresh and fallen teak leaves.

Materials and methods
Plant material
The fresh and fallen leaves of T.grandis were collected from Thongphaphum and Phitsanulok silviculture research station. The powder (50g) of leaves were soaked in methanol(250ml) at room temperature for 7 days. After Evaporate the solvent by rotary vacuum evaporator.

Anti-bacterial activity
The modified method of anti-bacterial activity was checked against S. epidermidis and S. aureus and P. acnes s by disc diffusion method. Leaves extract of T. grandis was dissolved in methanol and was tested at 500 µg/disc. Pure bacterial culture take 4-5 colonies with a loop transfer colony to 2 ml in Mueller-Hinton Broth (MHB) and incubate at 37 °C for 18-24 hrs. Adjust turbidity with 0.85% NSS (Normal saline solution) absorbance to 0.08-0.13 at 625 nm. by spectrophotometer. Dip a sterile cotton swab into the MHA and allow the surface of the medium to dry for 3-5 minutes. Loaded with the sample 10 µl and using sterile forceps place paper disc put on the surface of the inoculated and dried plate. incubate at 37°C for 18-24 hrs. After the diameter of inhibition zone and compared with antibiotic Gentamycin (Tendencia, Eleonor A. 2004).

Anti-tyrosinase activity
The modified method of anti-tyrosinase activity in the present study. 25 U/ml of tyrosinase enzyme (20 µl) mixed with phosphate buffer pH 6.8 (80 µl) and added 1500 µg/ml of the sample (60 µl). Then, added into 96 well plate was incubated at 25°C in the dark room for 10 min. After added 2.5 mM of L-dopachrome (40 µl) and incubated at 25°C in the dark room for 20 min. The dopachrome was checked in the absorbance at 475 nm with microplate reader. The percent inhibition of tyrosinase activity was calculated as % Inhibition = (A – B) – (C– D)/ (A – B) ×100. A is the absorbance at 475 nm with control, B is the absorbance at 475 nm with Blank control, C is the the absorbance at 475 nm with sample and D is the absorbance at 475 nm with blank sample (Chang and Tseng 2006).