RESUMEN
Lime (Citrus aurantifolia Swingle) is one of the major citrus fruits and widely consumed, but there is limited evidence about its health-promoting properties. Hence, an investigation was conducted to understand the chemopreventive effects of lime juice on pancreatic cancer cells and the possible mechanism for induction of apoptosis using Panc-28 cells. Freeze-dried lime juice was extracted with different solvents, such as chloroform, acetone, MeOH, and MeOH/water (8:2). The chloroform extract showed the highest (85.4 and 90%) radical-scavenging activity by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) methods at 624 microg/mL, whereas the MeOH/water extract showed the lowest (<20%) activity. The active components were identified by high-performance liquid chromatography (HPLC) using a C-18 column as rutin, neohesperidin, hesperidin, and hesperitin. Furthermore, the limonoids identified are limonexic acid, isolimonexic acid, and limonin. All of the extracts of lime juice inhibited Panc-28 cancer cell growth. The MeOH extract exhibited the maximum activity, with an IC50 value of 81.20 microg/mL after 72 h. The inhibition of Panc-28 cells was in the range of 73-89%, at 100 microg/mL at 96 h. The involvement of apoptosis in induction of cytotoxicity was confirmed by expression of Bax, Bcl-2, casapase-3, and p53. The results of the present study clearly indicate that antioxidant activity is proportionate to the content of flavonoids and proliferation inhibition ability is proportionate to the content of both flavonoids and limonoids.
Asunto(s)
Apoptosis/efectos de los fármacos , Citrus aurantiifolia/química , Frutas/química , Neoplasias Pancreáticas/patología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Antineoplásicos Fitogénicos , Antioxidantes/análisis , División Celular/efectos de los fármacos , Línea Celular Tumoral , Flavonoides/análisis , Humanos , Limoninas/análisisRESUMEN
Citrus limonoids have shown to inhibit the growth of cancer in colon, lung, mouth, stomach and breast in animal and cell culture studies. For the first time in the present study, an attempt has been made to isolate antioxidant fractions and five limonoids from red Mexican grapefruit seeds. Defatted seed powder was successively extracted with hexane, ethyl acetate (EtOAc), acetone, methanol (MeOH) and MeOH/water and the extracts were concentrated under vacuum. Radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total phenolic content were also measured for comparison with the antioxidant capacity in the phosphomolybdenum method for the above extracts. Acetone and MeOH extracts, respectively, showed the highest (85.7%) and lowest (53.3%) radical scavenging activity, at 500 ppm. The total phenolic contents were found to be highest in the acetone extract (15.94%) followed by the MeOH extract (5.92%), ethyl acetate extract (5.54%) and water extract (5.26%). Antioxidant capacity of the extracts as equivalents to ascorbic acid (micromol/g of the extract) was in the order, EtOAc extract > acetone extract > water extract > methanol extract. Furthermore, the EtOAC and acetone extracts were loaded onto silica gel columns to obtain four limonoid aglycons. MeOH fraction was loaded onto a dowex-50 and sepabeads resin column to obtain a limonoid glucoside. The purity of the isolated five compounds was analyzed by HPLC using a C18 column and UV detection at 210 nm. Finally, the structures of the compounds were identified as obacunone, nomilin, limonin, deacetylnomilin (DAN) and limonin-17-beta-D-glucopyranoside (LG) using 1H and 13C NMR studies.