Southeast Asian J Trop Med Public Health 1998 Sep;29(3):599-604
Antitrypanosomal effects of traditional Chinese herbal medicines on bloodstream forms of Trypanosoma brucei rhodesiense in vitro.
Yabu Y, Nose M, Koide T, Ohta N, Ogihara Y
[Medline record in process]
The antitrypanosomal activity of traditional Chinese herbal medicines and these crude drug ingredients were determined using axenic cultured bloodstream forms of Trypanosoma b. rhodesiense which is one of the two causative agents of African sleeping sickness in man. The drugs tested were 8 traditional Chinese herbal medicines and these 14 crude drug ingredients. Of these traditional Chinese medicines examined, san'o-shasin-to and oren-gedoku-to showed most potent antitrypanosomal effect. The minimal effective concentration (MEC) which killed all bloodstream form populations within 24 hours of both drug exposure was 125 microg/ml. The 50% effective concentration (EC50) of san'o-shashin-to and oren-gedoku-to was 63 and 74 microg/ml, respectively. In the crude drug ingredients tested, Scutellaria baicalensis G. and Coptis japonica M. which are the main components of san'o-shasin-to and oren-gedoku-to, showed the most powerful antitrypanosomal activity. The MEC and EC50 value of these crude drug ingredients were 30 and 60 microg/ml, and 20 and 36 microg/ml.
Eksp Klin Farmakol 1998 Nov-Dec;61(6):31-5
The search for new anti-ulcer agents from plants in Siberia and the Far East.
[Article in Russian]
Amosova EN, Zueva EP, Razina TG, Turetskova VF, Azarova
OV, Krylova SG, Gol'dberg ED
Screening tests on mice with the use of a model of neurogenic damage to the stomach revealed antiulcerative activity in extracts of Amoor cork tree, Pacific Bergenia, Lespedeza dichromatic, Leuzea carthamoides, sea-buckthorn, common aspen, Manchurian nuts, Serratula coronarius, and Scutellaria baicalensis. It was proved that an extract of aspen cork produces a marked antiulcerative effect on being administered to animals with "acute" ulcers and in treatment of chronic peptic ulcer. The study of various drug forms of Serratula coronarius extracts (prepared from the bark and the bark and shoots) in experiments on mice (neurogenic ulcer) and rats (Aspirin ulcer) revealed the most marked gastroprotective effect of oil extracts of bark and shoots. A high antiulcerogenic activity of extracts prepared from grass and roots of Scutellaria baicalensis was demonstrated.
Eur J Cancer Prev 1998 Dec;7(6):465-71
Induction of quinone reductase by a methanol extract of Scutellaria baicalensis and its flavonoids in murine Hepa 1c1c7 cells.
Park HJ, Lee YW, Park HH, Lee YS, Kwon IB, Yu JH
The effect of extracts of scutellariae radix (Scutellaria baicalensis
Georgi) and its flavonoids, baicalin, baicalein and wogonin, on induction
of quinone reductase (QR) in the Hepa 1c1c7 murine hepatoma cell line was
examined. A significant and dose-dependent induction of QR activity was
observed in the methanol extract of scutellariae radix and baicalin. HPCL
analysis showed that baicalin was contained as a main component in the
methanol extract of scutellariae radix, indicating that baicalin may be
the major active principle of QR induction mediated by scutellariae radix
extract. To elucidate the mechanism of baicalin-mediated induction of QR
enzyme activity, the effect on QR mRNA levels in Hepa 1c1c7 cell cultures
was investigated. Using reverse transcriptase-polymerase chain reaction
techniques, time- and dose-dependent induction of QR mRNA levels by baicalin
were demonstrated in Hepa 1c1c7 cells. On the basis of these results, the
scutellariae radix extract or baicalin can be regarded as a readily available,
promising, novel cancer chemopreventive agent.
J Nat Prod 1998 Nov;61(11):1413-5
Baicalein, an alpha-glucosidase inhibitor from Scutellaria baicalensis.
Nishioka T, Kawabata J, Aoyama Y
Methanol extracts of Scutellaria baicalensis, Rheum officinale, and
Paeonia suffruticosa showed potent inhibitory activity against rat intestinal
sucrase. The active principles were identified as baicalein from the first
and methyl gallate from the last two plants. In addition to its activity
against the rat enzyme, baicalein also inhibited human intestinal sucrase
expressed in Caco-2 cells.
Biol Pharm Bull 1998 Oct;21(10):1067-71
Effects of Sho-saiko-to, San'o-shashin-to and Scutellariae Radix on intracellular Ca2+ mobilization in C6 rat glioma cells.
Kyo R, Nakahata N, Sakakibara I, Kubo M, Ohizumi Y
Glial cells are able to support neurons physically and functionally.
The present study was undertaken to determine the effects of Kampo medicines
on glial cell function, especially Ca2+ mobilization. C6 rat glioma cells
expressed H1-histamine, muscarinic cholinergic and adrenergic alpha1-receptors,
stimulation of which resulted in phosphoinositide hydrolysis and increase
in intracellular Ca2+ concentrations ([Ca2+]i). The water extracts of Sho-saiko-to
and San'o-shashin-to, Kampo medicines which contain Scutellariae Radix
(Ogon, the root of Scutellaria baicalensis GFORGI), inhibited histamine
(100 microM)-induced increase in [Ca2+]i in a concentration-dependent manner.
The water extract of Scutellariae Radix potently decreased [Ca2+]i in a
concentration-dependent manner. Sho-saiko-to, San'o-shashin-to and Scutellariae
Radix significantly inhibited histamine-induced accumulation of total [3H]inositol
phosphates, consistent with their inhibition of the increase in [Ca2+1]i.
These results suggest that Sho-saiko-to, San'o-shashin-to and Scutellariae
Radix inhibit Ca2+ mobilization mediated via an inhibition of phospholipase
C. The inhibitory effect may be important in interpreting the pharmacological
actions of above Kampo medicines.
J Pharm Pharmacol 1998 Oct;50(10):1179-82
Baicalin and baicalein, constituents of an important medicinal plant, inhibit intracellular Ca2+ elevation by reducing phospholipase C activity in C6 rat glioma cells.
Kyo R, Nakahata N, Sakakibara I, Kubo M, Ohizumi Y
Glial cells have a role in maintaining the function of neural cells.
This study was undertaken to clarify the effects of baicalin and baicalein,
flavonoids isolated from an important medicinal plant Scutellariae Radix
(the root of Scutellaria baicalensis Georgi), on glial cell function using
C6 rat glioma cells. Baicalin and baicalein caused concentration-dependent
inhibition of a histamine-induced increase in intracellular Ca2+ concentrations
([Ca2+]i). The potency of baicalein was significantly greater than that
of baicalin. The noradrenaline- and carbachol-induced increase in [Ca2+]i
was also inhibited by baicalein and both drugs inhibited histamine-induced
accumulation of total [3H]inositol phosphates, consistent with their inhibition
of the increase in [Ca2+]i. These results suggest that baicalin and baicalein
inhibit [Ca2+]i elevation by reducing phospholipase C activity. The inhibitory
effects of baicalin and baicalein on [Ca2+]i elevation might be important
in the interpretation of their pharmacological action on glial cells, such
as inhibition of Ca2(+)-required enzyme phospholipase A2.
Eksp Klin Farmakol 1998 Mar-Apr;61(2):54-6
A semisynthetic flavonoid from the Baikal skullcap (Scutellaria baicalensis) as an agent to enhance the efficacy of chemotherapy in experimental tumors.
[Article in Russian]
Razina TG, Zueva EP, Litvinenko VI, Kovalev IP
Eksp Klin Farmakol 1998 Jan-Feb;61(1):37-9
The modulating effects of preparations of Baikal skullcap (Scutellaria baicalensis) on erythron reactions under conditions of neurotic exposures.
[Article in Russian]
Dygai AM, Suslov NI, Skurikhin EG, Churin AA, Provalova
Preparations of Scutellaria baicalensis, namely its dry extract and the bioflavonoid baicalin stimulate erythropoiesis depressed in deprivation of the paradoxical phase of sleep. After a conflict situation, when hemopoiesis is activated, both drugs normalize it. The modulating effect of drugs on hemopoiesis in exposure to neurotic factors is a consequence of their influence on the functional state of the cell elements of the hemopoiesis-inducing microenvironment. The capacity of the Scutellaria baicalensis drugs for reducing the effect of psychoemotional stress on the blood system is apparently related to their influence on the adrenergic structures.
Z Naturforsch [C] 1997 Nov-Dec;52(11-12):817-23
Antioxidant activity of flavones from Scutellaria baicalensis in lecithin liposomes.
Gabrielska J, Oszmianski J, Zylka R, Komorowska M
The antioxidant effect of a trihydroxyflavone extract from Scutellaria baicalensis on oxidation induced by ultraviolet light, was studied with phosphatidylcholine liposome membrane. Also, as standards, the antioxidative activity of baicalin, wogonin, baicalein and butylated hydroxytoluene (BHT) was investigated. Comparison of the protective effects of the compounds studied against photoinduced lipid peroxidation in lecithin liposome membranes showed that: (1) the inhibitory effect of those compounds (at 1.2 mol% antioxidant content in liposomes) on TBA reactive materials from lipid peroxidation decreased in the order of baicalin > BHT approximately equal to Scutellaria baicalensis. These were found much greater than wogonin and baicalein; (2) the depressed effect of those compounds (at 1.1 mol% compounds content in liposomes) on the production of conjugated dienes (proportional to oxidation index) could be classified as follows: Scutellaria baicalensis approximately equal to baicalin > BHT, these three were found more active much greater than baicalein and wogonin. Results obtained by ESR measurement confirm that Scutellaria baicalensis extract and the BHT compound significantly depressed the effect of liposome oxidation. It was found that the new trihydroxyflavones of Scutellaria baicalensis, ensured a very satisfactory concentration-dependent protection of the liposome membrane against UV-induced oxidation. These findings suggest that some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases (for example in skin diseases) by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.
Eksp Klin Farmakol 1997 Nov-Dec;60(6):49-51
Effect of Scutellaria baicalensis extract on the immunologic status of patients with lung cancer receiving antineoplastic chemotherapy.
[Article in Russian]
Smol'ianinov ES, Gol'dberg VE, Matiash MG, Ryzhakov VM,
Boldyshev DA, Litvinenko VI, Dygai AM
Cytostatic therapy of patients with lung cancer is attended with decrease in the relative number of T-lymphocytes and their theophylline-resistant population. Patients who were given SB showed a tendency towards increase of these parameters during antitumor chemotherapy. The immunoregulation index (IRI) in this case was approximately twice the background values during the whole period of investigation. The inclusion of SB in the therapeutic complex promotes increase in the number of immunoglobulins A at a stable level of immunoglobulins G.
ABSTRACT:Eksp Klin Farmakol 1997 Nov-Dec;60(6):28-30
Dry extract of Scutellaria baicalensis as a hemostimulant in antineoplastic chemotherapy in patents with lung cancer.
[Article in Russian]
Gol'dberg VE, Ryzhakov VM, Matiash MG, Stepovaia EA, Boldyshev
DA, Litvinenko VI, Dygai AM
Hemopoiesis was studied in 88 patients with lung cancer during antitumor chemotherapy and its combination with a dry SB extract. Administration of the plant preparation was accompanied with hemopoiesis stimulation, intensification of bone-marrow erythro- and granulocytopoiesis and increase in the content of circulating precursors of the type of erythroid and granulomonocytic colony-forming units.
Effects of flavonoids isolated from scutellariae radix on the production of tissue-type plasminogen activator and plasminogen activator inhibitor-1 induced by thrombin and thrombin receptor agonist peptide in cultured human umbilical vein endothelial cells.
Kimura Y, Yokoi K, Matsushita N, Okuda H
The effects of different flavonoids isolated from the roots of Scutellaria baicalensis Georgi on the production of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) induced by thrombin and thrombin receptor agonist peptide, Ser-Phe-Leu-Leu-Arg-Asn-Pro-Asn-Asp-Lys-Tyr-Glu-Pro-Phe, have been examined in cultured human umbilical vein endothelial cells (HUVECs). Thrombin and thrombin receptor agonist peptide induced production of both t-PA and PAI-1 and the elevation of intracellular free calcium concentration ([Ca2+]i). Baicalein isolated from Scutellariae Radix dose-dependently inhibited PAI-1 production induced by thrombin and thrombin receptor agonist peptide; its concentrations for 50% inhibition (IC50) were 6.8 and 3.5 microM, respectively. Other flavonoids had no effect. In contrast, flavonoids isolated from Scutellariae Radix had no effect on production of t-PA induced by thrombin and thrombin receptor agonist peptide. Baicalein inhibited the elevation of [Ca2+]i induced by thrombin and thrombin receptor agonist peptide and, at a concentration of 1000 microM, slightly increased t-PA production. These findings suggest that the mechanism by which baicalein inhibits PAI-1 production induced by thrombin and thrombin receptor agonist peptide might be by reduction of [Ca2+]i elevation. The results suggest that baicalein in Scutellariae Radix might be active as a drug in the treatment of arteriosclerosis and thrombosis.
J Ethnopharmacol 1997 Jun;57(1):63-7
Effects of baicalein isolated from Scutellaria baicalensis on interleukin 1 beta- and tumor necrosis factor alpha-induced adhesion molecule expression in cultured human umbilical vein endothelial cells.
Kimura Y, Matsushita N, Okuda H
We examined the effects of nine flavonoids isolated from Scutellariae radix on interleukin-1 beta (IL-1 beta)- and tumor necrosis factor-alpha (TNF-alpha)-induced adhesion molecule expression in cultured human umbilical vein endothelial cells (HUVECs). Among them, we found that baicalein (5,6,7-trihydroxy flavone) dose-dependently inhibited IL-1 beta and TNF-alpha-induced endothelial leukocyte adhesion molecule-1 (ELAM-1) and intercellular adhesion molecule-1 (ICAM-1) expressions. Its 50% inhibitory concentrations (IC50) for the IL-1 beta-induced ELAM-1 and ICAM-1 expressions were 2.3 x 10(-5) M and 4.0 x 10(-5) M, respectively. The IC50 for the TNF-alpha-induced ELAM-1 and ICAM-1 expressions were 1.5 x 10(-5) M and 3.1 x 10(-5) M, respectively. In addition, protein C-kinase (PKC) inhibitor H7 also inhibited the ELAM-1 and ICAM-1 expressions induced by IL-1 beta and TNF-alpha.
J Nat Prod 1997 Jun;60(6):598-601
Effects of flavonoids isolated from scutellariae radix on fibrinolytic system induced by trypsin in human umbilical vein endothelial cells.
Kimura Y, Okuda H, Ogita Z
Studies on the effects of flavonoids isolated from the roots of Scutellaria baicalensis on the fibrinolytic system induced by trypsin in cultured human umbilical vein endothelial cells (HUVECs) showed that baicalein (1) strongly inhibited the reduction of t-PA production and the elevation of PAI-1 production induced by trypsin. The IC50 for PAI-1 production was 3.7 microM. In addition, wogonin (3), oroxylin A (5), skullcapflavone II (6), and 2',5,5',7-tetrahydroxy-6',8-dimethoxyflavone (7) inhibited the elevation of PAI-1 induced by trypsin, though less strongly; their IC50 were 105, 61, 110, and 88 microM, respectively. These findings suggest that baicalein prevents the thrombotic tendency induced by trypsin.
Res Commun Mol Pathol Pharmacol 1995 Oct;90(1):103-14
Protection by baicalein against ascorbic acid-induced lipid peroxidation of rat liver microsomes.
Gao D, Sakurai K, Chen J, Ogiso T
The effect of baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a flavonoid isolated from Scutellaria baicalensis Georgi, on lipid peroxidation in rat liver microsomes was studied. Ascorbic acid-induced lipid peroxidation in microsomes obtained from baicalein-treated rats was inhibited by treatment on different days and at different doses. Iron release induced by ascorbic acid from microsomes of baicalein-treated rats was markedly lower than from microsomes of control rats. However, no statistical differences in total, nonheme and nonprotein-bound (free iron) iron contents could be detected in the two microsomes. The degradation of calf thymus DNA, an indicator of free iron existence, was observed in the reactions of microsomes obtained from control and baicalein-treated rats with ascorbic acid in the presence of bleomycin. These results suggest that baicalein can inhibit lipid peroxidation in microsomes induced by ascorbic acid by forming an inert complex of iron.
Chung Kuo Chung Hsi I Chieh Ho Tsa Chih 1995 Aug;15(8):465-7
Clinical and experimental study on inhibitory effect of sanhuang mixture on platelet aggregation.
[Article in Chinese]
Huang WM, Yan J, Xu J
Sanhuang mixture (Xinmai capsule) is composed of Astragalus membranaceus, Coptis chinensis and Scutellaria baicalensis. It could inhibit platelet aggregation (PAG) induced by ADP in rats or by ADP and ADR in vivo. Patients with high PAG took Xinmai capsule for 4 weeks, the effective rate was 88.7%, which was same as the efficacy of aspirin 50 mg/day. In Syndrome Differentiation of TCM, the effective rate was the highest (92.3%) in the Syndrome of Qi Deficiency-Blood Stasis, and the lowest (72.7%) in the Syndrome of Stasis Phlegm and combined together.
Planta Med 1995 Apr;61(2):150-3
Pharmacological effects of methanolic extract from the root of Scutellaria baicalensis and its flavonoids on human gingival fibroblast.
Chung CP, Park JB, Bae KH
The methanolic extract from the root of Scutellaria baicalensis Georgi and its flavonoids, wogonin, baicalein, and baicalin were evaluated for anti-inflammatory action and the activatory effect on gingival fibroblasts. In LPS-induced production of IL-1 beta, three flavonoids at 1 microgram/ml expressed a significant (> 50%) inhibitory effect, similar to that of prednisolone. Moreover, the flavonoids inhibited IL-1 beta-induced synthesis of PGE2 and LTB4 considerably, although the effect of wogonin on LTB4 synthesis was marginal. In addition, three flavonoids exerted a moderate inhibition (33-36%) of collagenolytic activity, comparable to 40% inhibition by tetracycline. Meanwhile, the cellular activity of fibroblasts was augmented remarkably (40%) by baicalein (2) and slightly by baicalin (3) or wogonin (1). Consistent with the cellular activation, flavonoids enhanced the synthesis of both collagen and total protein in fibroblasts, in contrast to growth factors which increased only the synthesis of total protein. Although the effects of the methanolic extract resembled those of the flavonoids, the extract expressed a preferential effect on the synthesis of collagen and total protein.
Biol Pharm Bull 1995 Feb;18(2):295-9
Antiviral activity of plant flavonoid, 5,7,4'-trihydroxy-8-methoxyflavone, from the roots of Scutellaria baicalensis against influenza A (H3N2) and B viruses.
Nagai T, Suzuki Y, Tomimori T, Yamada H
We investigated effects of isoscutellarein-8-methylether (5,7,4'-trihydroxy-8-methoxyflavone, F36) from the roots of Scutellaria baicalensis on the single-cycle replication of mouse-adapted influenza viruses A/Guizhou/54/89 (H3N2 subtype) and B/Ibaraki/2/85 in Madin-Darby canine kidney (MDCK) cells. The agent suppressed replication of these viruses from 6 to 12 h after incubation in a dose-dependent manner by 50% at 20 microM and 90% at 40 microM, respectively. F36 (50 microM) reduced the release of B/Ibaraki virus in the medium by 90-93% when it was added to the MDCK cells at 0 to 4 h after incubation. The cell-associated virus determined by sialidase activity was also reduced by the treatment at 0 to 4 h. F36 (120 microM) inhibited the low pH-dependent membrane fusion of both the viruses with the liposome containing mixed gangliosides from bovine brain. However, the agent little affected the hemagglutination and RNA-dependent RNA polymerase activities of these viruses in vitro. These results suggest that F36 inhibits the replication of A/Guizhou and B/Ibaraki viruses at least partly by inhibiting the fusion of viral envelopes with the endosome/lysosome membrane which occurs at the early stage of the virus infection cycle. F36 (0.5 mg/kg) showed no antiviral activity against A/Guizhou and B/Ibaraki viruses in mice when administered intranasally 5 min prior to virus inoculation, whereas it significantly inhibited their proliferation in the mouse lung when administered intranasally 7 times (total 3.5 mg/kg) from 18 h before to 54 h after virus infection.
Antiviral Res 1995 Jan;26(1):11-25
Mode of action of the anti-influenza virus activity of plant flavonoid, 5,7,4'-trihydroxy-8-methoxyflavone, from the roots of Scutellaria baicalensis.
Nagai T, Moriguchi R, Suzuki Y, Tomimori T, Yamada H
When mouse-adapted influenza virus A/PR/8/34 (A/PR8) (10 PFU/cell) was adsorbed to Madin-Darby canine kidney (MDCK) cells at 4 degrees C for 1 h and incubated at 37 degrees C, release of the virus from the cells was detected in the medium from 4 h after incubation and reached to plateau at 8 h. However, 5,7,4'-trihydroxy-8-methoxyflavone (F36) from the roots of Scutellaria baicalensis significantly reduced this single-cycle replication of A/PR8 from 4 h to 12 h after incubation by dose-dependent manner and the dose which decrease the virus titer one tenth was 11 microM. F36 (50 microM) did not inhibit the adsorption of A/PR8 to MDCK cells, but reduced release of the virus in the medium, when it was added at 0 or 2 h after the incubation. The cell-associated virus determined by sialidase activity was also reduced by F36 treatment at 0 or 2 h. F36 also inhibited the fusion of A/PR8 with liposomes containing bovine brain mixed gangliosides at pH 5.0. However, F36 little affected on the elongation activity of the viral RNA-dependent RNA polymerase in vitro. These results suggest that F36 reduces the replication of A/PR8 by inhibiting the fusion of the virus with endosome/lysosome membrane which occurs at early stage of virus infection cycle. Whereas, when F36 was added to the MDCK cells infected with A/PR8 at 3 or 4 h after incubation, release of the virus in the medium was reduced but the cell-associated virus was increased in comparison with control.
Eur J Pharmacol 1994 Jan 4;251(1):91-3
Antiproliferative effect of baicalein, a flavonoid from a Chinese herb, on vascular smooth muscle cell.
Huang HC, Wang HR, Hsieh LM
The effects of baicalein, baicalin and wogonin, the flavonoids from Scutellaria baicalensis, on the proliferative responses of cultured rabbit vascular smooth muscle cells were studied. The proliferative response was determined from the uptake of tritiated thymidine. In rabbit vascular smooth muscle cells, all three flavonoids dose dependently inhibited the proliferative response induced by 5% fetal calf serum at the dose range of 10(-6) to 10(-4) M. Baicalin and wogonin were less effective than baicalein as inhibitors of the serum-induced smooth muscle cell proliferation, indicating that the three hydroxyl groups on positions 5, 6 and 7 seem to be necessary and sufficient for full inhibitory activity against the proliferative response of smooth muscle cells. Baicalein had a greater inhibitory effect on the proliferative reponse stimulated by platelet-derived growth factor than on serum-stimulated proliferation. Baicalein, a flavonoid with antiproliferative and lipoxygenase-inhibitory activities, may be useful as another template for the development of better drugs to prevent the pathological changes of atherosclerosis and restenosis.
Agents Actions 1993;39 Spec No:C49-51
Anti-inflammatory properties and inhibition of leukotriene C4 biosynthesis in vitro by flavonoid baicalein from Scutellaria baicalensis georgy roots.
Butenko IG, Gladtchenko SV, Galushko SV
Anti-inflammatory activity of baicalein (5,6,7-trioxyflavone-7-O-beta-D-glucuronide) was greater in the chronic inflammation model (rat adjuvant arthritis, ED50 = 120.6 mg/kg) than observed in the rat carrageenan-induced paw edema, ED50 > or = 200.0 mg/kg. A comparative study of the 5-lipoxygenase (5-LO) inhibitory activity of baicalein, BW 755 C, and hydroxamic acid arachidonate on leukotriene C4 (LTC4) biosynthesis by rat resident peritoneal macrophages stimulated with calcium ionophore (A 23186) showed that these drugs significantly inhibited LTC4 production, IC50: 9.5, 41.8, and 2.8 microM, respectively. This finding suggests that inhibition of the 5-LO pathway of arachidonic acid metabolism may be one of the mechanisms of baicalein's anti-inflammatory activity.
J Infect Dis 1992 Mar;165(3):433-7
Inhibition of human T cell leukemia virus by the plant flavonoid baicalin (7-glucuronic acid, 5,6-dihydroxyflavone).
Baylor NW, Fu T, Yan YD, Ruscetti FW
The ability of baicalin (7-glucuronic acid, 5,6-dihydroxyflavone), a flavonoid compound purified from the Chinese medicinal herb, Scutellaria baicalensis georgi, to inhibit human T cell leukemia virus type I (HTLV-I) was examined. Baicalin produced concentration-dependent inhibition of HTLV-I replication in productively infected T and B cells. Moreover, baicalin treatment selectively reduced the detectable levels of HTLV-I p19 gag protein in infected cells by greater than 70% at concentrations that produced insignificant effects on total cellular protein and DNA synthesis with no loss in cell viability. Resistance to HTLV-I infection and virus-mediated transformation was noted in uninfected peripheral blood lymphocytes pretreated with baicalin before cocultivation with lethally irradiated chronically infected cells. Baicalin inhibited reverse transcriptase activity in HTLV-I-infected cells as well as the activity of purified reverse transcriptase from Moloney murine leukemia virus and Rous-associated virus type 2. These results suggest that baicalin may be a potential therapeutic agent against HTLV-I-associated T cell diseases.
Chem Pharm Bull (Tokyo) 1992 Feb;40(2):531-3
Studies on inhibitors of skin tumor promotion. XI. Inhibitory effects of flavonoids from Scutellaria baicalensis on Epstein-Barr virus activation and their anti-tumor-promoting activities.
Konoshima T, Kokumai M, Kozuka M, Iinuma M, Mizuno M, Tanaka
T, Tokuda H, Nishino H, Iwashima A
To search for possible anti-tumor-promoters, fourteen flavones obtained from the root of Scutellaria baicalensis were examined for their inhibitory effects on the Epstein-Barr virus early antigen (EBV-EA) activation by a short-term in vitro assay. Among these flavones, 5,7,2'-trihydroxy- and 5,7,2',3'-tetrahydroxyflavone showed remarkable inhibitory effects on the EBV-EA activation, and the effect of the latter on Raji cell cycle was also examined by flow cytometer. These two flavones exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.
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