Inhibition of Human T Cell Leukemia Virus by the Plant Flavonoid Baicalin (7-Glucuronic Acid, 5,6-Dihydroxyflavone)

Abstract

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.

High-yield production of scutellaria radix flavonoids (baicalein, baicalin and wogonin) by liquid-culture of Scutellaria baicalensis root-derived cells

“…On other hand, various physiologic activities of these flavonoids have been studied. The inhibitory effects of baicalein and baicalin on expansion of human viruses (Bayer et al, 1992;Wu et al, 1995), and a protective effect of baicalin on renal cell injury (Yokozawa et al, 1999) have been reported. It was also reported that baicalein, baicalin and wogonin showed suppression activity against the production of nitric oxide/prostaglandin E 2 (Chen et al, 2001;Chi et al, 2001) and proliferation of cancer cells (Chan et al, 2000;Chen et al, 2002;Matsuzaki et al, 1996;Okita et al, 1993;Yano et al, 1994).…”

Baicalin induces human mucoepidermoid carcinoma Mc3 cells apoptosis in vitro and in vivo

“…Many laboratory studies on animals and cell lines have shown that baicalin, one of the main active compounds of Scutellaria baicalensis (Fig. 1), has effects in inhibiting cell proliferation, inducing cell apoptosis, modulating cell cycle, as well as up-regulating p53, bax and p21 proteins [7][8][9][10]. In contrast, some other studies demonstrated that baicalin possesses potent antiapoptotic properties [11][12][13].…”

Baicalein 6-<i>O</i>-β-d-Glucopyranuronoside Is a Main Metabolite in the Plasma after Oral Administration of Baicalin, a Flavone Glucuronide of Scutellariae Radix, to Rats

“…1) as its main active constituent. BG and its aglycone, baicalein (B), have wide-ranging pharmacological effects, such as antiallergic, 1) anti-inflammatory, 2) antiviral, 3,4) antiproliferative, 5) and antitumor 6) effects, and also show strong antioxidant activity. 7,8) In addition, they inhibit prostaglandin E2 production, and prevent the gene expression of inducible nitric oxide synthase and cyclooxygenase-2.…”