A New nor-Sesquiterpene, Khusynoic Acid and Other Non-Volatile Anticancer Compounds From Vetiveria zizanioides Root

In present study, non-volatile cytotoxic phytoconstituents of Vetiveria zizanioides roots have been explored. The root extract afforded a new nor-sesquiterpene (an azulene derivative) (1), phenolic acid (2), flavonoid (3), flavonoid glycosides (4, 5) and sterol glycoside (6). The crude extract, solvent-partitioned fractions, and isolated compounds (1, 3, 4, 5, and 6) were screened for in vitro cytotoxic activity against the HCT-116 (human colon cancer) cell line. In parallel, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH and ABTS assays), and HPLC profiling gave comprehensive insight into the phytochemical profile. Among all fractions, n-butanol fraction exhibited the highest levels of phenolics, flavonoids, and antioxidant activity while n-hexane fraction showed highest cytotoxic potential (IC₅₀ = 105.23 µg/mL). Compound 5 showed the most potent cytotoxic effect (IC₅₀ = 10.29 µg/mL), while compounds 1 (45.28 µg/mL), 3 (20.22 µg/mL), 4 (48.95 µg/mL), and 6 (36.02 µg/mL) also showed significant activity. Further, Compounds 1, 3, 4, 5, and 6 showed no cytotoxicity toward the RAW 264.7 cell line. The study highlights the cytotoxic potential of V. zizanioides roots and its non-volatile constituents, with compound 5 showing the highest activity. Compounds 1, 4, and 6 are reported for the first time from its root.