Three new rotenoids (1–3), two new isoflavonoids (4 and 5), and six known analogues (6–11) were isolated from a n-hexane partition of a methanol extract of the fruits of Millettia caerulea, with the structures of the new compounds elucidated by analysis of their spectroscopic data. The relative configurations of the rotenoids were determined by interpretation of their NMR spectroscopic data, and their absolute configurations were established using ECD spectra and specific rotation values. All compounds isolated were evaluated for their cell growth inhibitory activity against the HT-29 human colon cancer cell line, and the known compounds, (−)-3-hydroxyrotenone (6) and (−)-rotenone (7), were found to be potently active. When tested in a NF-κB inhibition assay, compound 6 showed activity. This compound, along with the new compound, (−)-caeruleanone D (1), and the known compound, ichthynone (8), exhibited K-Ras inhibitory potency. Further bioactivity studies showed that the new compounds, (−)-3-deoxycaeruleanone D (2) and (−)-3-hydroxycaeruleanone A (3), and the known compounds 8 and 11 induced quinone reductase in murine Hepa 1c1c7 cells.

In view of the continuous growth of the botanical dietary supplement industry and the increased popularity of lesser known or exotic botanicals, recent findings are described on the phytochemical composition and biological activities of five selected fruits consumed in the United States, namely, açaí, noni, mangosteen, black chokeberry, and maqui berry. A review of the ethnomedicinal uses of these plants has revealed some similarities ranging from wound-healing to the treatment of fever and infectious diseases. Laboratory studies on açaí have shown both its antioxidant and anti-inflammatory activities in vitro, and more importantly, its neuroprotective properties in animals. Anthraquinones and iridoid glucosides isolated from noni fruit induce the phase II enzyme quinone reductase (QR), and noni fruit juice exhibited antitumor and antidiabetic activities in certain animal models. Antitumorigenic effects of mangosteen in animal xenograft models of human cancers have been attributed to its xanthone content, and pure α-mangostin was shown to display antineoplastic activity in mice despite a reported low oral bioavailability. Work on the less extensively investigated black chokeberry and maqui berry has focused on recent isolation studies and has resulted in the identification of bioactive secondary metabolites with QR-inducing and hydroxyl-radical scavenging properties. On the basis of the safety studies and toxicity case reports described herein, these fruits may be generally considered as safe. However, cases of adulteration found in a commercialized açaí product and some conflicting results from mangosteen safety studies warrant further investigation on the safety of these marketed botanical dietary supplements.

Melanodiol 4″-O-protocatechuate (1) and melanodiol (2) represent novel flavonoid derivatives isolated from a botanical dietary supplement ingredient, dried black chokeberry (Aronia melanocarpa) fruit juice. These non-crystalline compounds possess an unprecedented fused pentacyclic core with two contiguous hemiketals. Due to having significant hydrogen deficiency indices, their structures were determined using computer-assisted structure elucidation software. The in vitro hydroxyl radical-scavenging and quinone reductase-inducing activity of each compound are reported, and a plausible biogenetic scheme is proposed

Bioassay-guided phytochemical investigation of a commercially available maqui berry (Aristotelia chilensis) extract used in botanical dietary supplement products led to the isolation of 16 compounds, including one phenolic molecule, 1, discovered for the first time from a natural source, along with several known compounds, 2–16, including three substances not reported previously in A. chilensis, 2, 14, and 15. Each isolate was characterized by detailed analysis of NMR spectroscopic and HRESIMS data, and tested for their in vitro hydroxyl radical scavenging and quinone-reductase inducing biological activities. A sensitive and accurate LC-DAD-MS method for the quantitative determination of the occurrence of six bioactive compounds, 6, 7, 10–12, and 14, was developed and validated using maqui berry isolates purified in the course of this study as authentic standards. The method presented can be utilized for dereplication efforts in future natural product research projects, or to evaluate chemical markers for quality assurance and batch-to-batch standardization of this botanical dietary supplement component.

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