| In vitro: |
| J Nat Prod. 2011 Jul 22;74(7):1621-9. | | Synergy-directed fractionation of botanical medicines: a case study with goldenseal (Hydrastis canadensis).[Pubmed: 21661731] | It is often argued that the efficacy of herbal medicines is a result of the combined action of multiple constituents that work synergistically or additively. Determining the bioactive constituents in these mixtures poses a significant challenge.
METHODS AND RESULTS:
We have developed an approach to address this challenge, synergy-directed fractionation, which combines comprehensive mass spectrometry profiling with synergy assays and natural products isolation. The applicability of synergy-directed fractionation was demonstrated using the botanical medicine goldenseal (Hydrastis canadensis) as a case study. Three synergists from goldenseal were identified, sideroxylin, 8-desmethyl-sideroxylin, and 6-desmethyl-sideroxylin. These flavonoids synergistically enhance the antimicrobial activity of the alkaloid berberine (also a constituent of H. canadensis) against Staphylococcus aureus by inhibition of the NorA multidrug resistance pump. The flavonoids possess no inherent antimicrobial activity against S. aureus; therefore, they could have been missed using traditional bioactivity-directed fractionation. The flavonoid synergists are present at higher concentration in extracts from H. canadensis leaves, while the antimicrobial alkaloid berberine is present at higher levels in H. canadensis roots.
CONCLUSIONS:
Thus, it may be possible to produce an extract with optimal activity against S. aureus using a combination of goldenseal roots and leaves. | | J Nat Prod. 2015 Jul 24;78(7):1748-51. | | An Isoflavone from Leiophyllum buxifolium and Its Antiproliferative Effect.[Pubmed: 26086179] |
METHODS AND RESULTS:
A new C-methylisoflavone, isosideroxylin (1), and a known C-methylflavone, sideroxylin (2), were isolated from the EtOAc extract of the leaves of Leiophyllum buxifolium. The two compounds were evaluated with the sulforhodamine B assay for their antiproliferative effects against ER(-) MDA-MB-231 and ER(+) MCF-7 breast cancer cell lines and the NIH3T3 mouse fibroblast cell line.
CONCLUSIONS:
Isosideroxylin (1) displayed a selective antiproliferative effect against MDA-MB-231 cells. |
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