Altholactone

Altholactone, a novel styryl-lactone induces apoptosis via oxidative stress in human HL-60 leukemia cells.[Pubmed:11992734]

Toxicol Lett. 2002 May 28;131(3):153-9.

Plant styryl-lactone derivatives isolated from Goniothalamus sp. are potential compounds for cancer chemotherapy. In this study, we have examined the mechanisms of apoptosis induced by Altholactone, a stryl-lactone isolated from the Malaysian plant G. malayanus on human HL-60 promyelocytic leukemia cells. Flow cytometric analysis of the externalization of phosphatidylserine (PS) using the annexin V/PI method on Altholactone treated HL-60 cells showed a concentration-dependent increase of apoptosis from concentrations ranging from 10.8 (2.5 microg/ml) to 172.4 microM (40 microg/ml). Pre-treatment with the antioxidant N-acetylcysteine (1 mM) completely abrogated apoptosis induced by Altholactone, suggesting for the involvement of oxidative stress. Further flow cytometric assessment of the level of intracellular peroxides using the fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) confirmed that Altholactone induced an increase in cellular oxidative stress in HL-60 cells which was suppressed by N-acetylcysteine. In summary, our results demonstrate for the first time that Altholactone induced apoptosis in HL-60 cells occurs via oxidative stress.

Altholactone induces apoptotic cell death in human colorectal cancer cells.[Pubmed:22105918]

Phytother Res. 2012 Jun;26(6):926-31.

Resistance of colorectal cancer (CRC) to the available chemotherapy reveals the demand for identification of new anticancer agents. We evaluated the antitumour potential of Altholactone, a naturally occurring bioactive compound isolated from Goniothalamus spp. (Annonaceae) hooks, against CRC cells. Antitumour activity of Altholactone was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the propidium iodide method. Apoptosis mediators involved were assessed using biochemical inhibitors and Western blotting analysis. Results revealed that Altholactone induced varying degrees of apoptosis in CRC cells but not in normal fibroblasts. Dissection of the Altholactone-induced apoptotic signalling pathway revealed that Altholactone activated caspase-dependent and -independent apoptotic pathways. Activation of caspase-4 appeared to be the initiating event in the caspase-dependent apoptotic pathway. Pre-treatment of CRC cells with the antioxidant N-acetylcysteine (NAC) significantly inhibited activation of caspase-4 and Altholactone-induced apoptosis. These results indicate that Altholactone induces selective cytotoxicity against colon carcinoma cells and warrants further clinical evaluation.

Altholactone displays promising antimicrobial activity.[Pubmed:21642933]

Molecules. 2011 Jun 3;16(6):4560-6.

The antimicrobial activity of Altholactone, a naturally extracted styryllactone isolated from Goniothalamus malayanus, was determined against Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) and Gram negative (E. coli ATTC 35218, S. typhi ATTC 14023 and P. aeruginosa ATCC 27853) reference bacteria and against the fungus C. albicans ATTC 10231. Different concentrations of Altholactone (0, 12, 25, and 50 mug/mL) were used. Results revealed that Altholactone inhibited the growth of all tested microbes except P. aeruginosa ATCC 27853 in a dose-dependent manner, with the highest cytotoxic effects occurring at 50 mug/mL. The average of the inhibition zones of the different concentrations was between 0-30 mm. Furthermore, Altholactone-induced antimicrobial activity against the more sensitive microbes was assessed by measuring the minimal inhibitory concentration (MIC). Results indicated that Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) cells were more sensitive to Altholactone than Gram negative ones (E. coli ATTC 35218, S. typhi ATTC 14023). C. albicans showed moderate sensitivity. These results indicate that Altholactone might be a potential antimicrobial agent, particularly in ciprofloxacin-refractory S. aureus and E. faecalis infections. Further investigations are required to illustrate the mechanism(s) by which Altholactone produces its antimicrobial effects.

Role of altholactone in inducing type II apoptosis signalling pathway and expression of cancer-related genes in cervical carcinoma HeLa cell line.[Pubmed:23494867]

Cell Biol Int. 2013 May;37(5):471-7.

Goniothalamus species (Annonaceae) is a shrub that grows in the rainforest of tropical Asia. Several compounds have been isolated and exhibit the potential use for cancer treatment. In this work, Altholactone isolated from Goniothalamus macrophyllus was investigated for its cytotoxicity, apoptosis signalling and the expression of cancer-related genes in the cervical carcinoma HeLa cells. Cytotoxicity was evaluated by MTT assay. Apoptotic characteristics were evaluated by morphological studies. Caspase-3 activity was detected using a fluorogenic substrate. Cytochrome c release from mitochondria and protein Bid were determined by Western blotting and cancer-related genes expression by RT-PCR. The results demonstrated that Altholactone was cytotoxic to HeLa (IC50 = 9.6 mug/mL), and apoptotic cell death was manifested by appearance of chromatin condensation and caspase-3 activation, which was inhibited by specific inhibitors of both caspase-8 and -9. Release into the cytosol of cytochrome and cleavage of Bid occurred. Altholactone also caused a decrease in bcl-2 and an increase in p53 expression. These unique properties of Altholactone suggest a potential for cancer chemotherapy.