Hua-Yew Cheng

Antiherpes simplex virus type 2 activity of casuarinin from the bark of Terminalia arjuna Linn.

Casuarinin, a hydrolyzable tannin isolated from the bark of Terminalia arjuna Linn. (Combretaceae), was investigated for its antiviral activity on herpes simplex type 2 (HSV-2) in vitro. Results showed that the IC(50) of casuarinin in XTT and plaque reduction assays were 3.6+/-0.9 and 1.5+/-0.2 microM, respectively. The 50% cytotoxic concentration for cell growth (CC(50)) was 89+/-1 microM. Thus, the selectivity index (SI) (ratio of CC(50) to IC(50)) of casuarinin was 25 and 59 for XTT and plaque reduction assays, respectively. Casuarinin continued to exhibit antiviral activity even added 12 h after infection. During the attachment assay, casuarinin was shown to prevent the attachment of HSV-2 to cells. Furthermore, casuarinin also exhibited an activity in inhibiting the viral penetration. Interestingly, casuarinin was virucidal at a concentration of 25 microM, reducing viral titers up to 100,000-fold. This study concludes that casuarinin possesses anti-herpesvirus activity in inhibiting viral attachment and penetration, and also disturbing the late event(s) of infection.

Antiviral properties of prodelphinidin B-2 3'-O-gallate from green tea leaf

Prodelphinidin B-2 3′-O-gallate, a proanthocyanidin gallate isolated from green tea leaf, was investigated for its anti-herpes simplex virus type 2 properties in vitro. Prodelphinidin B-2 3′-O-gallate exhibited antiviral activity with IC50 of 5.0 ± 1.0 μM and 1.6 ± 0.3 μM for XTT and plaque reduction (PRA) assays, respectively. Cytotoxicity assay had shown that prodelphinidin B-2 3′-O-gallate possessed cytotoxic effect toward Vero cell at concentration higher than its IC50. The 50% cytotoxic concentration for cell growth (CC50) was 33.3 ± 3.7 μM. Thus, the selectivity index (SI) (ratio of IC50 to CC50) for XTT assay and PRA was 6.7 and 20.8, respectively. Prodelphinidin B-2 3′-O-gallate significantly reduced viral infectivity at concentrations 10 μM or more. Result of time-of-addition studies suggested that prodelphinidin B-2 3′-O-gallate affected the late stage of HSV-2 infection. In addition, it was also shown to inhibit the virus from attaching and penetrating into the cell. Thus, prodelphinidin B-2 3′-O-gallate was concluded to possess antiviral activity with mechanism of inhibiting viral attachment and penetration, and disturbing the late stage of viral infection.

Baicalin-Induced Apoptosis is Mediated by Bcl-2-Dependent, but not p53-Dependent, Pathway in Human Leukemia Cell Lines

Acute lymphoblastic leukemia (ALL), especially T-acute lymphoblastic leukemia (T-ALL), is a common childhood malignant neoplastic disorder. Chemotherapy agents, particularly those that can induce apoptosis, are the major intervening strategy in the treatment of ALL. In this study, we investigated in T-ALL cell line, CCRF-CEM, the in vitro cytotoxic effect and the mechanism of action of baicalin, a compound extracted from Scutellaria baicalensis Georgi and S. rivularis Benth (Labiateae). Results demonstrated that baicalin displayed a remarkable cytotoxic effect in CCRF-CEM, with an IC(50) value of 10.6 microg/ml. It triggered apoptotic effect by fragmentizing cellular DNA and arrested the cell cycle at G(0)/G(1) phase. Baicalin (37.5 microg/ml) had not effected the expression of p53 and Fas protein. It was shown to decline the expression of Bcl-2 (22.0 pg/ml), which consequently caused the loss (52.7%) of transmembrane potential (Delta Psi m) in the mitochondria after 72 hours of treatment. Baicalin (37.5 microg/ml) also elevated the amount of cytosolic cytochrome c (19.2 microg/ml), which finally triggered the activation of caspase-3 (50.1 pmol/min). In conclusion, baicalin was found to induce apoptosis in T-ALL cell lines through multiple pathways. This finding encourages further investigation of baicalin in its role as a potential candidate for chemotherapeutic agents in T-ALL.

In vitro Anti-leukemic and Antiviral Activities of Traditionally Used Medicinal Plants in Taiwan

Medicinal plants have been historically used as treatment for different kinds of human diseases. In this study, hot water (HW) extract of five Taiwanese traditionally used medicinal plants was evaluated for their in vitro anti-leukemic (including anti-K562, L1210, P3HR1, Raji and U937 leukemia cells) and antiviral (including HSV-1 and HSV-2) activities. Results showed that Blumea lacera exhibited broad anti-leukemic activity at magnitudes ranging from moderate to mild and Ixeris chinensis is effective at inhibiting the proliferation of K562 cells. B. lacera and Tithonia diversifolia suppressed the replication of HSV-1 and HSV-2, and had IC50 values below 100 microg/ml. The medicinal plants showed no cytotoxic effect at concentrations that inhibited HSV infection. It was, therefore, concluded that the HW extract of tested medicinal plants exhibited anti-leukemic and antiviral activities at different magnitudes of potency.

EUPHORBIA THYMIFOLIA SUPPRESSES HERPES SIMPLEX VIRUS-2 INFECTION BY DIRECTLY INACTIVATING VIRUS INFECTIVITY

1. The ethyl acetate (EtOAc) extract and 3‐O‐galloyl‐4,6‐(S)‐hexahydroxydiphenoyl‐d‐glucose (3OG46HG) of Euphorbia thymifolia Linnea have been shown to exhibit anti‐herpes simplex virus (HSV)‐2 activity in vitro. In the present study, we investigated the mode of action of these two compounds in suppressing HSV‐2 multiplication.

Antiviral Activity of Eight Commonly Used Medicinal Plants in Taiwan

In an effort to find new antiviral agents from natural products, hot water extracts of eight traditionally used medicinal plants in Taiwan were investigated in vitro for their activities against adenoviruses (ADV) and herpes simplex viruses (HSV). Results demonstrated that all extracts exhibited antiviral activity with different degrees of potency. Only two extracts were active in suppressing both HSV and ADV infections. Three extracts inhibited only ADV infection whereas one extract blocked only HSV infection. These results suggested that the aforementioned medicinal plants merit further investigation.

Anti-herpes Virus Type 2 Activity of Herbal Medicines from Taiwan

As an effort to explore new antiviral agents from natural products, 14 herbal medicines from Taiwan, which are traditionally used for the treatment of various diseases such as infection, gastric ulcer, edema, and rheumatism, etc., were tested for its anti-HSV-2 activity. Among them, only Cinnamomum insularimontanum Hay., Pinus massoniana Lamb., Plantago major Linn., and Uranaia crinita Desvaux. exhibited significant antiviral activity. The 50% inhibition concentration (IC 50) of C. insularimontanum, P. massoniana, U. crinita, and P. major was 180 ± 30, 250 ± 40, 350 ± 50, and 852 ± 50µg/ml, respectively, whereas the 50% cell cytotoxic concentration (CC 50) was 2210 ± 270, 1510 ± 180, 590 ± 70, and 1809 ± 200µg/ml, respectively. The selectivity index was in the range of 1.18-12.28. Thus, C. insularimontanum, P. major, P. massoniana, and U. crinita were concluded to possess anti-HSV-2 activity. Keywords: Herbal medicines, Cinnamomum insularimontanum Hay., Plantago major Linn., Pinus massoniana Lamb., Uranaia crinita Desvaux., anti-HSV-2 activity.

Prescriptions of Long Dan Xie Gan Tang, Yin Chen Hao Tang and WTTC Inhibit the Formation of Superoxide Radical and Scavenge Superoxide Radical in Vitro

Free radicals are reactive molecules that occur normally in organisms. However the excess generation of free radical can cause tissues and cells to be damaged, and might result in several diseases. In this study, the anti-superoxide radical formation and the superoxide radical scavenging activities of the water extract of prescriptions, Long Dan Xie Gan Tang (LDXGT), Yin Chen Hao Tang (YCHT) and WTTC, were evaluated by the xanthine/xanthine oxidase system and the cytochrome C reduction method, respectively. Results demonstrated that the water extract of the prescriptions suppressed superoxide anion formation and scavenged the radical in a dose-dependent manner. The potency on inhibiting the generation of superoxide radical was in the order of WTTC water extract (IC50=4.02±0.49 mg/ml)＞YCHT water extract (IC50=5.86±0.38 mg/ml)＞LDXGT water extract (IC50=6.52±0.38 mg/ml). The strength of superoxide radical scavenging activity was in the order of WTTC water extract (IC50=0.04±0.004 mg/ml)＞YCHT water extract (IC50=0.11±0.02 mg/ml)＞LDXGT water extract (IC50=0.55±0.18 mg/ml). In summary, the water extract of prescription LDXGT, YCHT and WTTC exhibit anti-superoxide radical activity in different magnitudes of potency in vitro.