Influences of Melatonin on the Growth of HeLa Cells

Aim To investigate the influences of melatonin (MT) on the growth of HeLa cells in vitro. Methods Theantiprolfferation activities of MT were evaluated in HeLa cells by means of trypan blue dye exclusion and MTT vital staining.The morphological changes of HeLa cells induced by MT were observed under transmission electronic microscope. Cell divisioncycle influenced by MT was assessed by a flow cytometry. Results MT produced a certain inhibition of HeLa cells at the con-centration of 2 mmol@ L-1 and prolonged the TD. The fraction of cells inhibited was 61.0%. The IC. so of HeLa cells exposed toMT for 96 h was 2.039 mmol@ L- 1. The flow cytometric analyses showed that exposure to MT for 72 h reduced the number ofHeLa cells in phase S. Under electronic microscope, the HeLa cells exposed to MT for 72 h displayed morphological changesof necrosis, apoptosis, more hetero-chromosome and less somatic chromosome. Conclusion MT showed certain influences onthe growth of HeLa cells. Its mechanism may probably be attributable to reduction of the number of cells in phase S.

Chiral rhodium(Ⅱ)-catalyzed asymmetric aldol-type interception of an oxonium ylide to assemble chiral 2,3-dihydropyrans

A chiral dirhodium complex is an effective and robust catalyst for asymmetric carbene transformations.However,dirhodiumcatalyzed asymmetric ylide interception processes are rare,mainly because of the dissociation of the metal catalyst before the stereo-determining step.Herein,we report a chiral dirhodium(Ⅱ)-catalyzed asymmetric annulation of vinyl diazoesters withα-hydroxyl ketones,which provides an efficient way to form chiral 2,3-dihydropyrans in good yields with excellent diastereoselectivities and enantioselectivities.This article is the first example of the chiral dirhodium complex–controlled asymmetric aldol-type interception of an in situ–formed oxonium ylide.The origin of the high stereoselectivity is well expounded via experimental and computational studies.These generated chiral products exhibit potent antiproliferation activity in three tested cancer cell lines,namely HCT116(colon cancer),A549(lung adenocarcinoma),and SJSA-1(osteosarcoma cancer).

Comparative assessment of phenolics,antioxidant and antiproliferative activities between Hippophae rhamnoides ssp.sinensis and H.tibetana leaf in Qinghai-Tibet Plateau

Hippophae rhamnoides ssp.sinensis(Rha)and H.tibetana(Tib)are two species of sea buckthorn which distribute in Qinghai-Tibet Plateau.Our results showed that both sea buckthorn leaf exhibited high total phenolic and flavonoid content,and Rha leaf showed much higher level.In addition,66 phenolic compounds were detected,belonging to classes of benzoic acid derivatives,flavonols,flavanols,flavanones,and so on.Classes of benzoic acid derivatives and flavonols were most abundant,among them ellagic acid and rutin were the most and second abundant phenols.Besides,methyl gallate,2,6-dihydroxybenzoic acid,4-hydroxybenzoic acid,gentisic acid,narcissin,astragalin,nicotiflorin,prunin,procyanidin B3,cyanidin 3-O-rutinoside chloride,delphinidin 3-glucoside,gallocatechin,taxifolin,aromadendrin and trans-3,3′,4′,5,5′,7-Hexahydroxyflavanone were the first time to be identified in SBT leaf.Furthermore,significant free radical scavenging effects of ABTS and DPPH,ferric reducing antioxidant ability,cellular antioxidant properties and anti-proliferation activity against HepG2 cells were observed in the aqueous ethanol extracts of sea buckthorn leaf.While Rha showed stronger inhibitory effects,which might due to the higher content of total phenolic and flavonoid profiles.Our finding clearly supported that Rha leaf as a wild and non-pollution plant could be a better choice as a healthy food resource.