Potent in vitro anti-mouth cancer (KB) and immunostimulating activities of the job’s tears (coix lachryma-jobi linn.) seed semi-purified extract cocktails containing linoleic acid

Abstract

The crude methanolic and hexane extracts of non-cooked, steamed and roasted from three Job's Tears cultivars were prepared and further semi-purified by liquid-liquid extraction techniques and silica gel column. The six single semi-purified extracts (F1-F6) were combined as nine cocktails (CT1, CT6, CT8, CT13, CT14, CT21, CT24, CT25 and CT31) according to the IC 50 values from the preliminary study and investigated for anti-proliferative and apoptotic induction on mouth cancer cell line (KB) and immunostimulating as well as antioxidative activities. The highest anti-proliferative activity was observed in CT13 showing the IC 50 value of 0.53±0.45 µg/mL which was higher than 5-fluorouracil and doxorubicin of 20.34 and 1.60 times, respectively. CT1 which was the combination of F1-F6 and CT13 which was the combination of F4-F6 exhibited significant strong synergistic activity with the combination index value (CI) of 0.28. CT1 at 200 µg/mL showed the highest percentages of apoptotic cells (40.65±10.97%) with no necrotic cells, but lower than cisplatin (100 µg/mL) of 2.18 times. CT14 gave the highest immunostimulating activity with the phagocytosis percentage of 13.0±1.7%, but lower than lipopolysaccharide of 1.08 times. CT31 gave the highest free radical scavenging and metal chelating activities with the SC 50 and MC 50 values of 0.73±0.07 and 1.99±0.24 µg/mL, but lower than ascorbic acid and EDTA of 18.25 and 4.33 times, respectively. The linoleic acid contents related to anti-cancer activity were also examined by HPLC. This study has demonstrated that CT1 composing of F1-F6 at the percentage ratio of 0.71:2.06:81.38: 8.47:4.92:2.46 was the potential cocktails of the semi-purified extracts from the Job’s Tears which can be further developed as a novel active compound for oral cancer treatment.