Baicalein, a flavonoid extracted from a methanolic extract of Oroxylum indicum inhibits proliferation of a cancer cell line in vitro via induction of apoptosis.
A methanolic extract of the fruits of Oroxylum indicum, which is widely used in traditional Chinese herbal medicine for its anti-inflammatory, anti-pyretic and anti-hypersensitivity effects, inhibited in vitro proliferation of HL-60 cells. The flavonoid baicalein was found as an active component in the extract. Analysis of freeze-dried fruits of the plant indicated that this component comprised about 4% of the material by dry weight. In this study, we investigated the in vitro effects of baicalein on the viability and induction of apoptosis in the HL-60 cell line. The cell viability after treating with baicalein for 24 h was quantified by counting viable cells using trypan blue staining. The results showed that baicalein caused a 50% inhibition of HL-60 cells at concentrations of 25-30 microM. The inhibition of proliferation of HL-60 cells due to 36-48 h exposure to 10 or 20 microM baicalein was associated with the accumulation of cells at S or G2M phases. However, proliferation inhibition at a higher dose may be associated with induction by apoptosis, as evidenced by the typical nuclear fragmentation using DNA fragmentation assay and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The results indicate that baicalein has anti-tumor effects on human cancer cells, and Oroxylum indicum extract could be used in supplementary cancer therapy.
Roy
M Kumar
MK
National Food Research InstituteFood Function Laboratory, Tsukuba, Japan. mkroy@affrc.go.jp
Nakahara
K
K
Na
Thalang V
TV
Trakoontivakorn
G
G
Takenaka
M
M
Isobe
S
S
Tsushida
T
T
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002470:Cell Survival; D002851:Chromatography, High Pressure Liquid; D053938:DNA Fragmentation / Q000187:drug effects; D044950:Flavanones / Q000494:pharmacology*; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D020287:In Situ Nick-End Labeling; D000432:Methanol; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet
D000972:Antineoplastic Agents, Phytogenic; D044950:Flavanones; D010936:Plant Extracts; D012997:Solvents; C006680:baicalein; D000432:Methanol