Phenolic content, antioxidant and allelopathic potential of Artemisia brevifolia Wall. ex DC. across the elevations of Western Himalayan region of Ladakh
Manzoor Hussain, Sajad Ahmed, Mohamed F. M. Ibrahim, Jabeena Khazir, Sheikh Showkat Ahmad, Rakesh Kr. Thakur, Renu Bhardwaj, Sumit G. Gandhi, Latif Ahmad Peer, Satwinderjeet Kaur, Bilal Ahmad Mir
Abstract
• A.brevifolia samples were collected from four locations between the altitude range 2800–4500 masl. • The content of total phenol and flavonoid decreases with increasing altitude. • The radical scavenging potential and phytotoxic effect of extracts decreases with an increase in altitude. • This decrease in phenolic content, antioxidant and allelopathic effect might be due to a declining number of competitive plants and available resources with increasing altitude. The climatic conditions change particularly in the high-altitude mountain ranges of the Himalayas. Artemisia brevifolia Wall. ex Dc., a pale green colored medicinal and aromatic plant, dominates different altitudinal locations in the Western Himalayan region of Ladakh. Metabolome analysis with antioxidative and allelopathic potential of the plant extracts from different altitudes was evaluated, with an aim to understand the interaction of the plant with its surroundings. The results showed decreasing concentration of total phenol and flavonoids with the increase in altitude. Metabolome analysis using FTIR points toward the presence of aromatic compounds, phenolic compounds and sesquiterpene lactones in all the samples with highest peak intensity in samples from Drass region of Ladakh. Overall, the metabolome analysis showed decreasing concentration of bioactive phenolics with the increase in altitude. The antioxidant activity of the sample extracts from low-altitude sites showed a higher inhibition percentage compared to high-altitude sites. Overall, the leaf extracts and powdered samples from different altitudes inhibited the germination and growth parameters of both dicotyledon ( Medicago sativa L.) and monocotyledon ( Triticum aestivum L.) in a concentration-dependent manner, under both in vitro and in vivo experimental conditions. Compared to germination rate and shoot length, the root length of both seedlings was strongly inhibited. The allelopathic potential of the extract and powdered samples also decreases with an increase in the altitude of the sampling site. These results indicate that the overall content of phenolics, radical scavenging potential and allelopathic potential decrease with an increase in altitude, which might be an adaptive strategy of A. brevifolia to conserve limited available resources at high altitudes.