Free-Radical Scavenging Capacity of Nine Botanical Extracts Used in Malaysian Nutraceuticals, with Untargeted Mass-Spectrometric Profiling of Broccoli and Brussels Sprout Extracts

Botanical extracts are core ingredients of Southeast Asian nutraceuticals, yet comparative data generated under identical laboratory conditions are scarce. This study screened nine botanical extracts—green tea (Camellia sinensis), broccoli (Brassica oleracea var. italica), Brussels sprout (B. oleracea var. gemmifera), pecah beling (Strobilanthes crispus), Sabah snake grass (Clinacanthus nutans), soursop leaf (Annona muricata), noni (Morinda citrifolia), roselle (Hibiscus sabdariffa) and a mixed-berry extract—under identical conditions in a single laboratory. Free-radical scavenging was measured with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Green tea extract was the most potent scavenger (half-maximal inhibitory concentration, IC50, 0.8 mg/mL in DPPH and 2.4 mg/mL in ABTS), followed by soursop leaf (1.9 and 5.2 mg/mL). Sabah snake grass, mixed berries, roselle, noni and pecah beling formed a moderate group at roughly one-twentieth to one-fortieth of the potency of green tea, while the two brassica extracts showed little direct scavenging at the solubility limit. Rankings were concordant between the two assays. Untargeted liquid chromatography–quadrupole time-of-flight tandem mass spectrometry of the brassica extracts returned profiles dominated by primary metabolites, consistent with bioactives that act by enzyme induction rather than by direct radical quenching. The results give formulators a uniform single-laboratory basis for comparing these ingredients, and show that chemical scavenging assays alone understate the contribution of brassica extracts.