Gastroprotective and antielastase effects of protein inhibitors from Erythrina velutina seeds in an experimental ulcer model

Trypsin and chymotrypsin inhibitors from Erythrina velutina seeds have been previously isolated by our group. In previous studies using a sepsis model, we demonstrated the antitumor and anti-inflammatory action of these compounds. This study aimed to evaluate the gastroprotective and antielastase effects of protein inhibitors from E. velutina seeds in an experimental stress-induced ulcer model. Two protein isolates from E. velutina seeds, with antitrypsin (PIAT) and antichymotrypsin (PIAQ) activities, were tested. Both protein isolates showed a high affinity and inhibitory effect against human neutrophil elastase, with 84% and 85% inhibition, respectively. Gastric ulcer was induced using ethanol (99%) in 6 groups of animals (female Wistar rats, n = 6). Before ulcer induction, these animals were treated for 5 days with one of the following: (1) PIAT (0.2 mg·kg−1), (2) PIAT (0.4 mg·kg−1), (3) PIAQ (0.035 mg·kg−1), (4) ranitidine hydrochloride (50 mg·kg−1), (5) saline solution (0.9%), or (6) no intervention (sham). Both PIAT and PIAQ protected gastric mucosa, preventing hemorrhagic lesions, edema, and mucus loss. No histologic toxic effects of PIAT or PIAQ were seen in liver and pancreatic cells. Our results show that protein isolates from E. velutina seeds have potential gastroprotective effects, placing these compounds as natural candidates for gastric ulcer prevention.

Differential Inhibition of Helicoverpa armigera (Hubner) Gut Proteinases by Proteinase Inhibitors of Okra and It's Wild Relatives

The seeds of ten genotypes and twenty-nine wild relatives of okra were analysed for the presence of trypsin, chymotrypsin, and Helicoverpa gut proteinases (HGPs) inhibitors (HGPIs), with the aim to identify potent inhibitors of H. armigera gut proteinases. Proteinase inhibitors (PIs) obtained from wild relatives of okra exhibited stronger inhibition of HGPs than the genotypes of okra. In in vitro inhibitory assay against HGPs, A. tuberculatus 90396 and 90515 showed high tryptic inhibitory (71.8% and 69.2%), chymotryptic inhibitory (68.5% and 66.2%), and Helicoverpa gut proteinase activity (70.2% and 68.2%). In electrophoretic profile showed the same variation in the number of trypsin inhibitors (TIs), chymotrypsin Inhibitors (CIs), and HGPIs isoforms with different intensities, whereas genotypes of okra mostly showed monomorphic profile. Maximum eight HGPIs isoforms were found in A. tuberculatus (90396 and 90515). In bioassay studies, significant reduction in weight of H. armigera larvae was found, when larvae fed on PIs obtained from A. tuberculatus (90396 and 90515). Thus, the result of the present investigation indicates that further exploration of PIs obtained from A. tuberculatus (90396 and 90515) will be helpful for developing PIs-based insect resistance management strategies.

Protease inhibitors of Acacia leucophloea gum extracts

Plant protease inhibitors (PIs) are very important for their defensive function against plant pathogens and predators. In present work trypsin and chymotrypsin inhibitors (PIs) from gum of one tree about seven species, Azadirachta indica, Acacia leucophloea, Acacia nilotica, Terminalia spp., Anogeissus latifolia, Mangifera indica and Moringa oleofera are studied. Protease inhibitory activity in gum extract was detected by dot blot assay. PI bands were resolved on electrophoresis gel and detected by Gel X-ray film contact print technique (GXCP). PIs from gum extracts were purified by gel filtration (Sephadex G-75). Among all gum extracts studied, the gum extract from Acacia leucophloea showed highest number of trypsin and chymotrypsin inhibitors. One PI from the Acacia leucophloea of 97.00kDa was purified and characterized. Purified PI was not destroyed by heat treatments up to 70ºC, but lost its activity when incubated at 80°C, showing moderate thermo stability.