Hydroxychavicol,a polyphenol from Piper betle leaf extract,induces cell cycle arrest and apoptosis in TP53-resistant HT-29 colon cancer cells

This study aims to elucidate the antiproliferative mechanism of hydroxychavicol(HC).Its effects on cell cycle,apoptosis,and the expression of c-Jun N-terminal kinase(JNK)and P38 mitogen-activated protein kinase(MAPK)in HT-29 colon cancer cells were investigated.HC was isolated from Piper betle leaf(PBL)and verified by high-performance liquid chromatography(HPLC),nuclear magnetic resonance(NMR),and gas chromatography-mass spectrometry(GC-MS).The cytotoxic effects of the standard drug 5-fluorouracil(5-FU),PBL water extract,and HC on HT-29 cells were measured after 24,48,and 72 h of treatment.Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h.Changes in phosphorylated JNK(pJNK)and P38(pP38)MAPK expression were observed up to 18 h.The half maximal inhibitory concentration(IC_(50))values of HC(30μg/mL)and PBL water extract(380μg/mL)were achieved at 24 h,whereas the IC_(50)of 5-FU(50μmol/L)was obtained at 72 h.Cell cycle arrest at the G0/G1 phase in HC-treated cells was observed from12 h onwards.Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells(P<0.05)was observed.High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells,but not in 5-FU-treated HT-29 cells(P<0.05).It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells,with these actions possibly mediated by JNK and P38 MAPK.

Piper betle leaf extract enhances the cytotoxicity effect of 5-fluorouracil in inhibiting the growth of HT29 and HCT116 colon cancer cells

Objective： The combination effect of Piperbetle （PB） and 5-fluorouracil （5-FU） in enhancing the cytotoxic potential of 5-FU in inhibiting the growth of colon cancer cells was investigated. Methods： HT29 and HCT116 cells were subjected to 5-FU or PB treatment. 5-FU and PB were then combined and their effects on both cell lines were observed after 24 h of treatment. PB-5-FU interaction was elucidated by isobologram analysis. Apoptosis features of the treated cells were revealed by annexin V/PI stain. High-performance liquid chromatography （HPLC） was performed to exclude any possible chemical interaction between the compounds. Results： In the presence of PB extract, the cytotoxicity of 5-FU was observed at a lower dose （IC^0 12.5 pmol/L） and a shorter time （24 h） in both cell lines. Both cell lines treated with 5-FU or PB alone induced a greater apoptosis effect compared with the combination treatment. Isobologram analysis indicated that PB and 5-FU interacted synergistically and antagonistically in inhibiting the growth of HT29 and HCT116 cells, respectively. Conclusions： In the presence of PB, a lower dosage of 5-FU is required to achieve the maximum drug effect in inhibiting the growth of HT29 cells. However, PB did not significantly reduce 5-FU dosage in HCT116 cells. Our result showed that this interaction may not solely contribute to the apoptosis pathway.

Chlorella vulgaris triggers apoptosis in hepatocarcinogenesis-induced rats

Chlorella vulgaris （CV） has been reported to have antioxidant and anticancer properties. We evaluated the effect of CV on apoptotic regulator protein expression in liver cancer-induced rats. Male Wistar rats （200-250 g） were divided into eight groups： control group （normal diet）, CDE group （choline deficient diet supplemented with ethionine in drinking water to induce hepatocarcinogenesis）, CV groups with three different doses of CV （50, 150, and 300 mg/kg body weight）, and CDE groups treated with different doses of CV （50, 150, and 300 mg/kg body weight）. Rats were sacrificed at various weeks and liver tissues were embedded in paraffin blocks for immunohistochemistry studies. CV, at increasing doses, decreased the expression of anti-apoptotic protein, Bcl-2, but increased the expression of pro-apoptotic protein, caspase 8, in CDE rats, which was correlated with decreased hepatoctyes proliferation and increased apoptosis as determined by bromodeoxy-uridine （BrdU） labeling and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling （TUNEL） assay, respectively. Our study shows that CV has definite chemopreventive effect by inducing apoptosis via decreasing the expression of Bcl-2 and increasing the expression of caspase 8 in hepatocarcinogenesis-induced rats.

Anti-migratory effects of Piper betle leaf aqueous extract on cancer cells and its microtubule targeting properties

Piper betle(PB),also known as ubeter,in Malay language,is a tropical Asian vine.PB leaves are commonly chewed by Asians along with betel quid.It contains phenols such as eugenol and hydroxychavicol along with chlorophyll,P-carotene,and vitamin C(Salehi et al.,2019).Extracts from PB leaves have various medicinal properties including anticancer,antioxidant,anti-inflammatory,and antibacterial effects(Salehi et al.,2019).Previous research has shown that PB induces cell cycle arrest at late S or G2/M phase and causes apoptosis at higher doses(Wu et al.,2014;Guha Majumdar and Subramanian,2019).