The Pre-Harvest Flushing Effect on The Phytochemical Composition and Antioxidant Activity of Cannabis sativa Fluorescence, Leaves and Twigs

Abstract

Cannabis (Cannabis sativa L.) contains many important bioactive compounds such as terpenes and cannabinoids (THC and CBD). These compounds were used in medical benefits and recreational uses. During the cultivation process, proper care throughout the growth cycle is crucial. One key step is nutrient flushing before harvest which involves rinsing nutrients from the plant's growing medium by watering with plain water. This process was typically done 2-3 weeks before harvesting. Therefore, this research aims to investigate the chemical composition using GCMS techniques. Also, total phenolic, flavonoid, tannin, chlorophyll and carotenoid contents were determined. The antioxidant activity of the fluorescence, leaves, and twigs from flushed and unflushed before harvest were analyzed. The results showed that the flushing process affected to chemical composition which are cannabinoids and triterpenes in twigs and didn’t affect to fluorescence and twigs. Moreover, this process increased total phenolics, flavonoids and tannin in fluorescence. Also increased total flavonoids, tannin and chlorophyll in twigs and increased total carotenoid in leaves. For antioxidant activity, the IC50 of fluorescence, leaves and twigs were increased by DPPH assay and FRAP value of fluorescence and twig were increased. Therefore, it can be concluded that the flushing before harvest affects the chemical composition and antioxidant activity, which may be applied to the cultivation of other plants.