Perspective Studies on Novel Anticancer Drugs from Natural Origin:A Comprehensive Review

Toxicological outcome of phthalate exposure on male fertility: Ameliorative impacts of the co-administration of N-acetylcysteine and zinc sulfate in rats

Background

Reports have shown that humans are consistently exposed to environmental toxicants such as phthalate (PHT) during their daily activities. This results in reproductive dysfunction and infertility-related issues as already noted in human and experimental animals. We therefore designed this study to investigate fertility outcome in phthalate-exposed male rats treated with N-acetylcysteine (NAC) and zinc sulfate (ZnSO4) with the view of providing a therapeutic alternative to reproductive toxicity caused by phthalate. The research was done in two phases. In phase 1, thirty-five male Wistar rats were randomly assigned to one of five (n = 7) groups given the following treatments for 21 days: group A was given distilled water as a control, while groups B, C, D, and E were given phthalate (750 mg/kg/day). Animals in groups C to E were also given ZnSO4 (0.5 mg/kg/day), N-acetylcysteine (100 mg/kg/day), and ZnSO4 (0.5 mg/kg/day) + N-acetylcysteine (100 mg/kg/day) in addition to phthalate. In phase 2, animals from groups in phase 1 were mated with females for fecundity testing.

Results

The result shows alteration in testicular and epididymis weight and testis/epididymis ratio, semen parameters, sperm capacitation and acrosome reaction, sperm DNA, serum Zn and Mg, testicular mitochondria apoptosis mechanisms (TNF-α and BCL-2), and testicular Ca2+-ATPase as well as fecundity outcome in the phthalate-treated group. However, ZnSO4 and NAC successfully ameliorated the deleterious effects of phthalate on semen parameters, sperm capacitation and acrosome reaction, serum electrolyte and mitochondria apoptosis mechanisms, and testicular electrogenic Ca2+-ATPase in phthalate-induced male rats with a better outcome in the combined therapy. Pregnancy outcome and litter sizes were also higher in the combined therapy when also compared with the phthalate-treated groups.

Conclusion

According to the result, ZnSO4 and NAC increased fertility outcome in phthalate-treated male rats through enhancement of testicular BCL-2, serum electrolyte, testicular Ca2+ATPase pumps, and cytoprotection.

Synthesis and biological evaluation of new 2-methoxyestradiol derivatives: Potent inhibitors of angiogenesis and tubulin polymerization

Here, we report the structural optimization of a hit natural compound, 2-ME₂ (2-methoxyestradiol), which exhibited inhibitory activity but low potency on tubulin polymerization, anti- angiogenesis, MCF-7 proliferation and metastasis in vitro and in vivo. A novel series of 3,17-modified and 17-modified analogs of 2-ME₂ were synthesized and investigated for their antiproliferative activity against MCF-7 and another five different human cancer cell lines leading to the discovery of 9i. 9i bind to tubulin colchicine site tightly, inhibited tubulin polymerization and disrupted cellular microtubule networks. Cellular mechanism studies revealed that 9i could induce G2/M phase arrest by down-regulated expression of p-Cdc2, P21 and cell apoptosis by regulating apoptosis-related proteins (Parp, Caspase families) in a dose-dependent manner. Importantly, 9i significantly inhibited HUVEC tube formation, proliferation, migration and invasion. The inhibitory effect against angiogenesis in vivo was confirmed by zebrafish xenograft. Furthermore, 9i could effectively inhibit the proliferation and metastasis of MCF-7 cells in vitro and in zebrafish xenograft. The satisfactory physicochemical property and metabolic stability of 9i further indicated that it can act as a promising and potent anti-angiogenesis, inhibiting proliferation and metastasis of breast cancer agent via targeting tubulin colchicine binding site.

Hepatoprotective and hematological effects of Justicia secunda Vahl leaves on carbon tetrachloride induced toxicity in rats

Justicia secunda Vahl is an exotic plant that is used to treat medical problems. We investigated the hepatoprotective and hematological effects of aqueous extracts of J. secunda leaves on carbon tetrachloride induced toxicity in rats. Leaf extracts were prepared using hot and cold extraction methods to obtain a hot extract of J. secunda leaves (JSHAE) and a cold extract of J. secunda leaves (JSCAE). Total phenol and flavonoid measurements and antioxidant assays were performed to determine the extract with the greater antioxidant activity. JSHAE was the more effective extract for treatment of carbon tetrachloride (CCl₄) induced hepatotoxicity and hepatotoxicity in rats. Silymarin was used as a standard for comparison. We found that JSHAE contained more total phenol and flavonoid than JSCAE. JSHAE exhibited significantly greater ferric reducing antioxidant power and 1,1-diphenyl-2-picryl hydrazyl and thiobarbituric acid scavenging activity than JSCAE. We also found that in vivo, 100 and 200 mg/kg JSHAE significantly reduced plasma aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and total bilirubin levels following CCl₄ induced toxicity compared to untreated rats. JSHAE treated animals exhibited white blood cell, red blood cell, hemoglobin, hematocrit, platelet and procalcitonin levels that were comparable to control animals. Liver sections of rats treated with 200 mg/kg. JSHAE exhibited no abnormalities.