Influence of leaf type, genotype, and location on bioactivities and assessment of genetic diversity in teak (Tectona grandis L. f.)

Abstract

Marked variation in biological activities was observed among teak (Tectona grandis L. f.) leaf extracts as influenced by leaf type, tree genotype, and planting location. Fresh leaves generally exhibited stronger antibacterial activity than fallen leaves, with significant differences detected among plus trees originating from Chiang Mai, Phrae, Sukhothai, Lampang, and Khon Kaen and grown at the Thongphaphum and Phitsanulok Silviculture Research Stations. Among all samples, the Phrae plus tree cultivated at Thongphaphum showed the highest antibacterial inhibition against the tested microorganisms. Methanol extracts demonstrated antibacterial, anti-tyrosinase, and anti-inflammatory activities, while sequential extraction of Phrae plus tree leaves using hexane and dichloromethane yielded fractions with potent antibacterial effects, indicating promising potential for the development of new antibacterial agents. Genetic analysis based on sequence-related amplified polymorphism (SRAP) markers revealed similarity coefficients ranging from 0.67 to 1.00, reflecting low to moderate genetic diversity among the studied germplasm, with some samples exhibiting nearly identical genetic profiles. Overall, the observed variation in biological activities was closely associated with both genetic background and environmental conditions, providing valuable information for teak germplasm selection and the utilization of leaf-derived bioactive compounds in product development.