Chemical Composition, Genetic Diversity, Antibacterial, and Antioxidant Activities of <i>Juniperus tibetica</i> Kom.

This study investigates the variations in chemical, genetic, and biological (antibacterial and antioxidant) profiles of 17 populations of Juniperus tibetica Kom. (J. tibetica) to assess their potential for further production development. Correlations between chemical composition and the biological activities of essential oils (EOs) and ethanol (EtOH) extracts of J. tibetica were evaluated. GC-MS analysis identified 74 compounds in J. tibetica needles EOs, with populations YS01 and YS04 exhibiting the highest number of constituents (70 components). Variations were observed among 17 populations in terms of total phenolic content (ranging from 4.49 to 6.69 mmol equiv. GAE/g) and total flavonoid content (ranging from 2.43 to 3.44 mmol equiv. QUE/g). The contents of medicinally valuable compounds, namely quercitrin and amentoflavone, also varied considerably. Population BM06 showed the highest quercitrin content (4.39 mg/g dry weight), whereas population BM07 exhibited the highest amentoflavone content (3.53 mg/g dry weight). Variations in antioxidant activities (DPPH, ABTS, and FRAP) and antibacterial activities were observed among the populations, with population BM03 displaying the highest antioxidant and antibacterial capacities. Based on an exploratory PLS model, compounds tentatively associated with antioxidant activity included α-pinene, abietadiene, hedycaryol, γ-elemene, β-eudesmol, and γ-terpinene. Those correlated with antibacterial activity included abietal, epi-α-muurulol, palustral, γ-elemene, and α-pinene. Genetic diversity of the 17 J. tibetica populations was assessed with SSR markers. Collectively, these results provide preliminary descriptive data on the chemical, genetic, and biological variation in J. tibetica. These observations may serve as a basis for hypothesis generation in future studies on quality evaluation, resource conservation, and further investigation.