Chemical composition and vasodilator activity of different Alpinia zerumbet leave extracts, a potential source of bioactive flavonoids

Abstract A polyphenol-rich extract with an expressive vasodilator effect was obtained from fresh leaves of Alpinia zerumbet (AZ), a medicinal plant. The vasodilator effects of AZ obtained from different extraction conditions were studied in perfused mesenteric vascular bed, and total polyphenol content (TPC) was determined for all samples. Chemical composition of AZ was analyzed by UHPLC/ESI-QTOF-MS, and a list of putative compounds was obtained by a molecular network. Briefly, results obtained indicate a 50% hydroethanolic extract from fresh leaves (AZE4) as the best extraction condition, presenting the greatest vasodilator effect (ED 50 = 7.1 µg ± 1.73) and TPC (16.30 mg GAE/g ± 0.44). Flavonoids were detected as main constituents and alpinetin, kaempferol-3-O-glucuronide, (-)- epicatechin and pinocembrin were identified as major compounds. The last effective extraction condition was 50% hydroethanolic extract from dried leaves without heating, which showed the smallest vasodilator response (ED 50 = 29.1 µg ± 4.3) and TPC (6.35 mg GAE/g ± 0.08), reinforcing the use of fresh leaves and heating step to improve extracts performance. The vasodilator effect and the main flavonoid composition of AZE4 provide experimental support for the indication of this extract as a potential source of bioactive flavonoids for the treatment of cardiovascular diseases.