Antitumor Activity of a Lectin Purified from Punica granatum Pulps against Ehrlich Ascites Carcinoma (EAC) Cells

Abstract

Background: Lectins are carbohydrate-binding proteins with various pharmacological activities, such as antimicrobial, antidiabetic, antioxidant, and anticancer. Punica granatum fruit extract has traditional uses, however, the anti-cancer activity of purified lectin isolated from P. granatum pulp is yet to be reported.

Objective: The goals of this study are purification, characterization of the lectin from P. granatum, and examination of the purified lectin's anticancer potential.

Methods: Diethylaminoethyl (DEAE) ion-exchange chromatography was used to purify the lectin, and SDSPAGE was used to check the purity and homogeneity of the lectin. Spectrometric and chemical analysis were used to characterize the lectin. The anticancer activity of the lectin was examined using in vivo and in vitro functional assays.

Results: A lectin, designated as PgL of 28.0 ± 1.0 kDa molecular mass, was isolated and purified from the pulps of P. granatum and the lectin contains 40% sugar. Also, it is a bivalent ion-dependent lectin and lost its 75% activity in the presence of urea (8M). The lectin agglutinated blood cells of humans and rats, and sugar molecules such as 4-nitrophenyl-α-D-manopyranoside and 2- nitrophenyl -β- D-glucopyranoside inhibited PgL's hemagglutination activity. At pH ranges of 6.0-8.0 and temperature ranges of 30°C -80°C, PgL exhibited the highest agglutination activity. In vitro MTT assay showed that PgL inhibited Ehrlich ascites carcinoma (EAC) cell growth in a dose-dependent manner. PgL exhibited 39 % and 58.52 % growth inhibition of EAC cells in the mice model at 1.5 and 3.0 mg/kg/day (i.p.), respectively. In addition, PgL significantly increased the survival time (32.0 % and 49.3 %) of EAC-bearing mice at 1.5 and 3.0 mg/kg/day doses (i.p.), respectively, in comparison to untreated EAC-bearing animals (p < 0.01). Also, PgL reduced the tumor weight of EAC-bearing mice (66.6 versus 39.13%; p < 0.01) at the dose of 3.0 mg/kg/day treatment. Furthermore, supplementation of PgL restored the haematological parameters toward normal levels deteriorated in EAC-bearing animals by the toxicity of EAC cells.

Conclusion: The results indicated that the purified lectin has anticancer activity and has the potential to be developed as an effective chemotherapy agent.

Keywords: Punica granatum; cell growth inhibition; chemotherapy; lectin; survival rate; tumour weight..