Lih Geeng Chen

Wogonin, baicalin, and baicalein inhibition of inducible nitric oxide synthase and cyclooxygenase-2 gene expressions induced by nitric oxide synthase inhibitors and lipopolysaccharide

We previously reported that oroxylin A, a polyphenolic compound, was a potent inhibitor of lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In the present study, three oroxylin A structurally related polyphenols isolated from the Chinese herb Huang Qui, namely baicalin, baicalein, and wogonin, were examined for their effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. The results indicated that these three polyphenolic compounds inhibited LPS-induced NO production in a concentration-dependent manner without a notable cytotoxic effect on these cells. The decrease in NO production was in parallel with the inhibition by these polyphenolic compounds of LPS-induced iNOS gene expression. However, these three compounds did not directly affect iNOS enzyme activity. In addition, wogonin, but not baicalin or baicalein, inhibited LPS-induced prostaglandin E2 (PGE2) production and COX-2 gene expression without affecting COX-2 enzyme activity. Furthermore, N-nitro-L-arginine (NLA) and N-nitro-L-arginine methyl ester (L-NAME) pretreatment enhanced LPS-induced iNOS (but not COX-2) protein expression, which was inhibited by these three polyphenolic compounds. Wogonin, but not baicalin or baicalein, similarly inhibited PGE2 production and COX-2 protein expression in NLA/LPS or L-NAME/LPS-co-treated RAW 264.7 cells. These results indicated that co-treatment with NOS inhibitors and polyphenolic compounds such as wogonin effectively blocks acute production of NO and, at the same time, inhibits expression of iNOS and COX-2 genes.

Inducible nitric oxide synthase inhibitor of the Chinese herb I. Saposhnikovia divaricata (Turcz.) Schischk

L-Arginine derived nitric oxide (NO) and its derivatives, such as nitrogen dioxide and peroxynitrite, play a role in inflammation and also possibly in the multistage process of carcinogenesis. Four furanocoumarins and eight chromones isolated from the dried root of Saposhnikovia divaricata (Fang Feng in Chinese) and evaluated for their effects on the synthesis of NO induced by lipopolysaccharide (LPS) in macrophage cell line RAW 264.7. The inhibition of nitrite production, as an index for NO released from the macrophage cells, was quantitatively analyzed by Griess reaction. The results showed that imperatorin and deltoin are potential NO production inhibitor, and their IC50 values for inhibition of nitrite production were 17.3 and 11.6 microg/ml, respectively. Western-blot analysis demonstrated that iNOS enzyme activity was not inhibited by treatment with imperatorin or deltoin, but revealed that both compounds inhibited the expression of the iNOS protein.

Gastroprotective activity of atractylenolide III from Atractylodes ovata on ethanol‐induced gastric ulcer in vitro and in vivo

Objectives The rhizome of Atractylodes ovata De Candolle is popularly used in traditional Chinese medicine to treat gastrointestinal diseases. However, the major gastroprotective compounds of A. ovata have not been identified. This study reports on the principal gastro‐ protective component of A. ovata.

Anti-inflammatory effects of resveratrol and oligostilbenes from vitis thunbergii var. taiwaniana against lipopolysaccharide-induced arthritis

Vitis thunbergii Sieb. and Zucc. var. taiwaniana Lu is an endemic plant in Taiwan used as a dietary supplement for bone health. In this study, human chondrocytes were induced to produce COX-2, MMP-3, -13, and PGE(2) by LPS. An (18)F-FDG microPET imaging system was used to evaluate the anti-inflammatory arthritic effects in vivo. Six stilbenes, resveratrol (1), (+)-ε-viniferin (2), ampelopsin C (3), ampelopsin A (4), (-)-vitisin B (5), and (+)-vitisin A (6), were isolated from the stem part of V. thunbergii, which displayed the strongest PGE(2) inhibition. Among these compounds, 1 significantly decreased COX-2 activity, PGE(2), MMP-3, and -13 production in vitro, and (18)F-FDG uptake and serum PGE(2) in rabbits in vivo. Anti-inflammatory effects were enhanced through the combined usage of 1 and other oligostilbenes. Taken together, the synergistic effects of 1 and oligostilbenes resulted in stem part extracts with lower 1 content displaying the better anti-inflammatory arthritis effects.

Antitumor activity of four macrocyclic ellagitannins from Cuphea hyssopifolia.

We evaluated the antitumor activities of four macrocyclic hydrolyzable tannin dimers, cuphiin D1, cuphiin D2, oenothein B and woodfordin C isolated from Cuphea hyssopifolia (Lythraceae). All significantly inhibited the growth of the human carcinoma cell lines KB, HeLa, DU-145, Hep 3B, and the leukemia cell line HL-60, and showed less cytotoxicity than adriamycin against a normal cell line (WISH). All four compounds inhibited the viability of S-180 tumor cells in an in vitro assay and an in vivo S-180 tumor-bearing ICR mice model. Oenothein B demonstrated the greatest cytotoxicity (IC50 = 11.4 microg/ml) against S-180 tumor cells in culture, while cuphiin D1 resulted in the greatest increase in survival on S-180 tumor-bearing mice (%ILS = 84.1%). Our findings suggest that the antitumor effects of these compounds are not only related to their cytotoxicity on carcinoma cell lines, but also depended on a host-mediated mechanism; they may therefore have potential for antitumor applications.

Inducible nitric oxide synthase inhibitors of Chinese herbs. Part 2: Naturally occurring furanocoumarins

Inducible nitric oxide synthase (iNOS)-dependent production of nitric oxide (NO) plays an important role in inflammation. The effects of various naturally occurring furanocoumarins on NO production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophage cells were evaluated in vitro. The results showed that angelicin, pimpinellin, sphondin, byakangelicol, oxypeucedanin, oxypeucedanin hydrate, xanthotoxin, and cnidilin are potential NO production inhibitors, and their IC50 values for inhibition of nitrite production were 19.5, 15.6, 9.8, 16.9, 16.8, 15.8, 16.6, and 17.7 microg/mL, respectively. Distinct structure-activity relationships were also revealed for the NO production inhibitory activities of these furanocoumarins. Activities of the angelicin type such as pimpinellin and sphondin were more potent than those of the psoralen type. Presence of a methoxy at the C6 position in the angelicin type seemed to be essential to augment the activity. Western blot analysis demonstrated that only sphondin dose-dependently inhibited the expression of the iNOS protein at 2.5-20 microg/mL. However, iNOS enzyme activity was stimulated with LPS for 12 h and sphondin was administered (20 microg/mL) for 24 h, which did not reasonably inhibit iNOS enzyme activity. L-NAME (100 microM), a known specific inhibitor of iNOS, was employed as a positive control with the same protocol and showed more than 50% inhibition activity. The results demonstrate that the NO production inhibitory activity of sphondin is due to the effect of iNOS expression, but not by direct inhibition of iNOS enzyme activity. Thus, sphondin may act as a potent inhibitor of NO production under tissue-damaging inflammatory conditions.

Wogonin, a bioactive flavonoid in herbal tea, inhibits inflammatory cyclooxygenase‐2 gene expression in human lung epithelial cancer cells

Wogonin, a naturally occurring plant flavonoid, is isolated from Chinese herbal plants Scutellaria baicalensis Georgi and S. barbata D. Don. The extract of S. baicalensis Georgi has been added to an assortment of health drinks or food supplements. Wogonin has been reported to exhibit anticancer and anti-inflammatory properties. Cyclooxygenase-2 (COX-2) is a key enzyme in the production of prostaglandins in inflammatory conditions. In this study, the effect of wogonin on phorbol 12-myristate 13-acetate (PMA)-induced COX-2 expression was investigated. It showed that wogonin inhibited PMA-induced COX-2 protein and mRNA levels in human lung epithelial cancer cells, and the mechanism of this inhibition was at the transcriptional level by using COX-2 gene promoter assay. Among various signal inhibitors, the mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor U0126 also inhibited PMA-induced COX-2 expression and COX-2 promoter activation. The activity of AP-1-driven promoter, but not nuclear factor-kappa B (NF-kappaB), was inhibited by U0126. The data indicated that MEK1/2-AP-1 is very important for PMA-induced COX-2 expression. Wogonin also inhibited PMA-induced AP-1 activation and the expression of c-Jun, a key component of AP-1. Taken together, it is suggested that wogonin inhibits PMA-induced COX-2 gene expression by inhibiting c-Jun expression and AP-1 activation in A549 cells.

Synthesis and anticancer activity of a novel series of 9-O-substituted berberine derivatives: A lipophilic substitute role

To alter its hydrophobicity, a series of compounds bearing 9-O-alkyl- or 9-O-terpenyl- substituted berberine were synthesized and evaluated for anticancer activity against human cancer HepG2 and HT29 cell lines. We found that the lipophilic substitute of 9-O-alkyl- and 9-O-terpenyl berberine derivatives plays a role in inhibiting the human cancer cell growth and its activity could be maximized with the optimized substitute type and chain length. Most strikingly, nonetheless, of the six compounds prepared, sample 8, a farnesyl 9-O-substituted berberine, showed either comparable or better cytotoxic activity against human cancer HepG2 cell line than that of berberine. Compound 8 had also shown a 104-fold antiproliferation activity in compare with berberine against human hepatoma HepG2 cell lines after 48 incubation hours. Further, in Hoechst 33258 and annexin V-FITC/PI staining analyses it induced apoptosis in HepG2 cells at lower concentration than that of berberine for 24h. Take all; farnesyl 9-O-substituted berberine could be a potential candidate for new anticancer drug development.

Ellagitannins from Terminalia calamansanai induced apoptosis in HL-60 cells.

Terminalia calamansanai (Blanco) Rolf. (Combretaceae) is used medicinally as lithontriptic in Philippines. The 70% acetone extracts of T. calamansanai leaves inhibited the viability of human promyelocytic leukemia HL-60 cells. 1-Alpha-O-galloylpunicalagin, punicalagin, 2-O-galloylpunicalin, sanguiin H-4, and methyl gallate were the main components isolated from T. calamansanai with the IC(50) values of 65.2, 74.8, 42.2, 38.0 and >100 microM, respectively, for HL-60 cells. Apoptosis of HL-60 cells treated with 1-Alpha-O-galloylpunicalagin, punicalagin, 2-O-galloylpunicalin, and sanguiin H-4 was noted by the appearance of a sub-G(1) peak in flow cytometric analysis and DNA fragmentation by gel electrophoresis. 2-O-Galloylpunicalin and sanguiin H-4 induced a decrease of the human poly(ADP-ribose)polymerase (PARP) cleavage-related procaspase-3 and elevated activity of caspase-3 in HL-60 cells, but not normal human peripheral blood mononuclear cells (PBMCs), suggesting that both compounds may be new candidates for drug development in the prevention and treatment of cancer.

Structural identification and bioactivities of red-violet pigments present in Basella alba fruits.

Mature Basella alba L. fruit, with dark blue skin and deep red-violet flesh, is a potential source of natural colorants. Its pigment components and bioactivities deserve particular attention and investigation. In this study, fruit flesh was extracted with 80% methanol (containing 0.2% formic acid) and subjected to solid-phase extraction, semipreparative HPLC isolation, mass spectrophotometric analysis, and structural elucidation. The major red pigment was identified as gomphrenin I. Its quantity increased with the increase of fruit maturity. The gomphrenin I extract yield from ripe fruits was 36.1 mg/100 g of fresh weight. In addition to gomphrenin I, betanidin-dihexose and isobetanidin-dihexose were also detected. The antioxidant activities of gomphrenin I determined by Trolox equivalent antioxidant capacity (TEAC), α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, and antioxidative capacity assays were equivalent to 534 μM Trolox, 103 μM butylated hydroxytoluene (BHT), 129 μM ascorbic acid, and 68 μM BHT at 180, 23, 45, and 181 μM, respectively. The anti-inflammatory function was tested at concentrations of 25, 50, and 100 μM in murine macrophages stimulated with lipopolysaccharide (LPS). The results revealed that gomphrenin I suppressed LPS-induced nitric oxide (NO) production in a dose-dependent manner and decreased PGE(2) and IL-1β secretions at the highest concentration tested. The transcriptional inhibitory activities of gomphrenin I on the expression of inflammatory genes encoding iNOS, COX-2, IL-1β, TNF-α, and IL-6 were also observed. It is of merit to identify gomphrenin I as a principal pigment of B. alba fruits and as a potent antioxidant and inflammatory inhibitor. These findings suggest that B. alba fruit is a rich source of betalains and has value-added potential for use in the development of food colorants and nutraceuticals.