Leaf Variegation Alters in Antioxidant Activity and Phenolic CompoundsConcentration of Indian Borage (Plectranthus amboinicus)

Plectranthus amboinicus (Indian borage) is used in folk medicine and culinary and presented a variegated version. This work aimed to evaluate the influence leaf variegation on chemical composition and biological activities of P. amboinicus and P. amboinicus “Variegata”. Hydroalcoholic extracts of herbs were evaluated for their preliminary phytochemistry; total flavonoid and rosmarinic acid content by spectrophotometry and HPLC methods, respectively; antioxidant activity on DPPH, ABTS, Fe2+ chelation ions and β-carotene/linoleic acid assays; and antiproliferative effects in saroma 180 cells by MTT assay. Preliminary phytochemistry showed that both plants present flavonoids, flavone and coumarins. P. amboinicus “Variegata” extract presented higher levels of flavonoid and rosmarinic acid and higher antioxidant activity in DPPH and ABTS assays, as well as P. amboinicus extract showed better antioxidant activity in the Fe2+ chelating activity and inhibition of β-carotene oxidation. Both extracts induced pronounced anticancer effects on sarcoma 180. We hypothesize that variegation promotes modulations in secondary metabolism, which leads to the increase of total flavonoids and rosmarin acid biosynthesis, interfering in the biological activities exhibited for P. amboinicus extracts.