Accumulation of secondary metabolites is a key process in the growth and development of plants under different biotic/abiotic constraints. Many studies highlighted the regulatory potential of UV-B treatment towards the secondary metabolism of plants. In the present study, we examined the impact of UV-B on the physiology and secondary metabolism of Withania coagulans, which is an important ayurvedic plant with high anti-diabetic potential. Results showed that in-vitro UV-B exposure negatively influenced chlorophyll content and photosynthetic machinery. However, Fv/Fm ratio was found non-significantly altered up to 3 h UV-B exposure. The maximum lipid peroxidation level was recorded with 46.8% higher malondialdehyde content in the plants supplemented with 5 h UV-B radiation, that was indicated the oxidative stress in W. coagulans. Conversely, UV-B treatment significantly increased the plant's stress protective compounds like carotenoids, anthocyanin, phenol and proline, in W. coagulans. Free radical scavenging activity was also significantly increased ~ 18% than the control with 3 h UV-B treatment. The maximum antioxidative enzymes activities were observed with the short-term (up to 3 h) UV-B treatment. Specifically, UV-B radiation exposure significantly increased the content of withaferin A and withanolide A in W. coagulans with maximum 1.38 and 3.42-folds, respectively. Additionally, withanolides biosynthesis related genes transcript levels were found over-expressed under the response of UV-B elicitation. The acquired results suggested that short-term UV-B supplementation triggers secondary metabolism along with combating oxidative stress via improving the antioxidative defense system in W. coagulans. Also, UV-B can be used as an efficient abiotic elicitor to increase pharmaceutical compounds (withanolides) production.

次生代谢产物的积累是植物在不同生物/非生物条件下生长发育的关键过程。许多研究强调了 UV-B 处理对植物次生代谢的调节潜力。在本研究中，我们研究了 UV-B 对 Withania coagulans 的生理和次级代谢的影响，Withania coagulans是一种重要的阿育吠陀植物，具有很高的抗糖尿病潜力。结果表明，体外UV-B 暴露对叶绿素含量和光合机制产生负面影响。然而，发现 Fv/Fm 比在 3 小时 UV-B 暴露后没有显着变化。在补充 5 小时 UV-B 辐射的植物中记录到最大脂质过氧化水平，丙二醛含量高 46.8%，这表明W. coagulans存在氧化应激。相反，UV-B 处理显着增加了植物的应激保护化合物，如凝结西葫芦中的类胡萝卜素、花青素、苯酚和脯氨酸. 与 3 小时 UV-B 处理的对照相比，自由基清除活性也显着增加约 18%。短期（长达 3 小时）UV-B 处理观察到最大的抗氧化酶活性。具体而言，UV-B 辐射暴露显着增加了W. coagulans中的 withaferin A 和 withanolide A 的含量，最大分别为 1.38 和 3.42 倍。此外，发现在 UV-B 诱导的响应下，withanolides 生物合成相关基因转录水平过度表达。获得的结果表明，短期补充 UV-B 可通过改善W. coagulans的抗氧化防御系统来触发次级代谢以及对抗氧化应激。. 此外，UV-B 可用作有效的非生物诱导剂，以增加药物化合物（withanolides）的产量。