Non-pungent functional food components in the water extracts of hot peppers

Bhut Jolokia, the hottest pepper in the world, Scotch Bonnet and Jalapeño are hot Capsicum spp. with 1001,304, 250,000–300,000 and 5000 Scoville Heat Units (SHUs), respectively. The SHU is also an indication of varying concentrations of lipid-soluble capsaicinoids present in these hot peppers. However, our studies using lipid peroxidation (LPO) and cyclooxygenase (COX-1 and -2) enzyme assay with the water extracts of these peppers showed similarity in inhibitory activities. Also, chromatographic analyses of water extracts of these hot peppers showed identical profiles except for the capsaicinoids. This prompted us to investigate the water-soluble compounds in these pepper extracts with LPO and COX enzyme inhibitory activities. A bioassay-guided investigation of the water extract of Scotch Bonnet pepper afforded compounds 1–6, also common in Jalapeño and Bhut Jolokia water extracts. Compounds 1–6 inhibited LPO by 73%, 45%, 20%, 43%, 16% and 72%, respectively, and COX-1 and -2 enzymes by 14–72% and 30–31%. Most of these compounds showed higher COX-1 inhibitory activity similar to aspirin, ibuprofen and naproxen. However, compound 5 showed higher COX-2 enzyme inhibition similar to Celebrex, a prescription non-steroidal anti-inflammatory (NSAID) drug. Compound 1 is novel; 2, 3, 5 and 6 were isolated from genus Capsicum for the first time.