β-Sitosterol Oxides From the Dried Stem of Salix gilgiana Inhibit the Proliferation of HL-60 Leukemic Cells

Abstract

Background: Salix gilgiana is a deciduous tree that grows in northern Japan, the Korean peninsula, eastern Russia along the Ussuri River, and northeast China. The stem of this tree is dried and consumed orally as a folk medicine. Our intensive screening of various plant materials found that the MeOH extract of its dried stem exhibited significant antiproliferative activity against HL-60 leukemic cells with an IC50 of 16 ppm. We systematically investigated the biologically active compounds of the MeOH extract of the dried stem of S. gilgiana. Methods: The MeOH extract of S. gilgiana dried stem was fractionated by a repeated chromatography monitored by antiproliferative activity against HL-60 leukemic cells. Five active compounds were isolated and the structures were elucidated by MS, 1H- and 13C-NMR spectroscopy, and X-ray analysis. Results: The active compounds were identified as 7-ketositosterol (I), 7β-hydroxysitosterol (II), 7α- hydroxysitosterol (III), (4-hydroxyphenyl)ethanol (IV), and (4-hydroxyphenyl)propan-1-ol (V). The strongest activity was found for 7α-hydroxysitosterol (III), with an IC50 of 8.4 µM. This is the first report of the isolation of these compounds from S. gilgiana. Conclusion: Five compounds were isolated by a repeated chromatography under the guidance of antiproliferative bioassay using HL-60. The structures were identified as three β-sitosterol oxides and two phenolic compounds. Since Salix species, namely, willow trees, have beneficial characteristics including rapid growth, easy cloning, and resistance to high humidity and dryness, they may be utilized as a relatively inexpensive tool for the efficient production of useful bioactive materials.

In vitro Antibacterial Activities, DPPH Radical Scavenging, and Molecular Modeling of Isolated Compounds from the Bark of Grewia ferruginea

“…Along with compound 37, compound 38 was identi ed as a minor with relative amount of ca. 30% (calculated from peak area of respective proton, Figure S21) and proposed as 6-keto-5,6-dihydro-β-sitosterol by comparing with NMR spectral data of 7-keto-5,6-dihydro-β-sitosterol [40], β-sitosterol [30], 7-keto-β -sitosterol [39], and 6ketocholestanol [41]. The COSY (Figure S26) and HMBC (Figure S25) were used to con rm the structures of compounds.…”

“…Compound 37 was observed as light yellow amorphous solid and showed TLC spot at R f 0.5 using EtOAc: n-Hexane (3:2). From NMR data recorded (Figure S21-S24 and summarized as Table 5), compound 37 was characterized by comparing the 13 C-NMR data with 13 C-NMR spectral data reported for 7-keto-β-sitosterol [38,39].…”

“…Δδ ketocholestanol [41] and 13 C-NMR spectral data (C-18 to C-29) reported for 7-keto-β -sitosterol [39] were used (Table 5). Compound 39 was observed as white solid and showed TLC spot at R f 0.5 with n-hexane: EtOAc (1:4) as mobile phase.…”