Koichiro Ohnuki

Inhibitory effects of the leaves of loquat (eriobotrya japonica) on bone mineral density loss in ovariectomized mice and osteoclast differentiation

The loquat, Eriobotrya japonica Lindl. (Rosaceae), is a small tree native to Japan and China that is widely cultivated for its succulent fruit. Its leaves are used as an ingredient of a tasty tea called Biwa cha in Japanese. The anti-osteoporosis effects of the leaves of loquat in vitro and in vivo have been investigated. After 15 days of feeding normal diet or diet supplemented with 5% loquat leaves, the body weight, viscera weights, and bone mineral density (BMD) of both groups of eight ovariectomized (OVX) mice were compared. The result showed that the loss of BMD in loquat-fed mice was significantly prevented in three parts of the body, especially in the trabecular bone of the head (P < 0.05), abdomen (P < 0.01), and lumbar (P < 0.05) compared to the control group. No hypertrophy in the uterus by the loquat leaves diet was observed. The effect of the extract (447.25 g) prepared from the dried leaves of loquat (2.36 kg) was further studied on RANKL-induced osteoclast differentiation and cell viability. The extract suppressed the differentiation of osteoclasts under 50, 125, 250, and 500 μg/mL. Through bioactivity-guided fractionation, ursolic acid (1) was isolated and inhibited osteoclast differentiation under 4 and 10 μg/mL. It was concluded that loquat leaves possess the potential to suppress ovariectomy-induced bone mineral density deterioration.

Inhibition of neuraminidase by Ganoderma triterpenoids and implications for neuraminidase inhibitor design.

Neuraminidase (NA) inhibitors are the dominant antiviral drugs for treating influenza in the clinic. Increasing prevalence of drug resistance makes the discovery of new NA inhibitors a high priority. Thirty-one triterpenoids from the medicinal mushroom Ganoderma lingzhi were analyzed in an in vitro NA inhibition assay, leading to the discovery of ganoderic acid T-Q and TR as two inhibitors of H5N1 and H1N1 NAs. Structure-activity relationship studies revealed that the corresponding triterpenoid structure is a potential scaffold for the design of NA inhibitors. Using these triterpenoids as probes we found, through further in silico docking and interaction analysis, that interactions with the amino-acid residues Arg292 and/or Glu119 of NA are critical for the inhibition of H5N1 and H1N1. These findings should prove valuable for the design and development of NA inhibitors.

Multiple uses of Essential Oil and By-Products from Various Parts of the Yakushima Native Cedar (Cryptomeria Japonica)

This article presents multiple potential uses of the Yakushima native cedar (Cryptomeria japonica), known in Japan as the Yaku-sugi tree. The Yaku-sugi was divided into four parts: leaves, branches with leaves, branches, and stems. We obtained the essential oil, hydrosol, distillation residue, and distillation wastewater from the trees. Essential oil and hydrosol were determined to be volatile organic compounds. All samples were screened for the following bioactivities: antioxidative, antibacterial, and anti-melanogenesis activities. Freeze-dried distillation residue was tested to assess whether it had a deodorizing effect. The main component of the leaf essential oil was found to be monoterpenes. In contrast, the stem essential oil mainly contained sesquiterpenes. In terms of bioactivities, the leaf essential oil showed antibacterial activity and the stem essential oil showed anti-melanogenesis activity. Distillation residue and wastewater showed many activities, including antioxidant, antibacterial, and anti-melanogenesis activities. Moreover, the residue had a deodorizing effect against ammonia.

Anti-obesity activity of Yamabushitake (Hericium erinaceus) powder in ovariectomized mice, and its potentially active compounds

Hericium erinaceus (H. erinaceus) improves the symptoms of menopause. In this study, using ovariectomized mice as a model of menopause, we investigated the anti-obesity effect of this mushroom in menopause. Mice fed diets containing H. erinaceus powder showed significant decreases in the amounts of fat tissue, plasma levels of total cholesterol, and leptin. To determine the mechanism, groups of mice were respectively fed a diet containing H. erinaceus powder, a diet containing ethanol extract of H. erinaceus, and a diet containing a residue of the extract. As a result, H. erinaceus powder was found to increase fecal lipid levels in excreted matter. Further in vitro investigation showed that ethanol extract inhibited the activity of lipase, and four lipase-inhibitory compounds were isolated from the extract: hericenone C, hericenone D, hericenone F, and hericenone G. In short, we suggest that H. erinaceus has an anti-obesity effect during menopause because it decreases the ability to absorb lipids.

Hericium erinaceus extracts alter behavioral rhythm in mice

Hericium erinaceus (HE), an edible mushroom, has been used as a herbal medicine in several Asian countries since ancient times. HE has potential as a medicine for the treatment and prevention of dementia, a disorder closely linked with circadian rhythm. This study investigated the effects of the intake of HE extracts on behavioral rhythm, photosensitivity of the circadian clock, and clock gene mRNA expression in the suprachiasmatic nucleus (SCN), a central clock, in mice. Although the HE ethanol extract only affected the offset time of activity, the HE water extract advanced the sleep-wake cycle without affecting the free-running period, photosensitivity, or the clock gene mRNA expression in SCN. In addition, both extracts decreased wakefulness around end of active phase. The findings of the present study suggest that HE may serve as a functional food in the prevention and treatment of Alzheimers disease and delayed sleep phase syndrome.

A novel resveratrol derivative selectively inhibits the proliferation of colorectal cancer cells with KRAS mutation

Resveratrol is a polyphenolic compound in many edible foods including grapes, peanuts, and berries. Several studies have revealed the beneficial effects of resveratrol against various diseases such as heart disease, diabetes, obesity, neurological disorders, and cancer. A recent study showed that resveratrol inhibits the proliferation of HCT116 human colorectal cancer cells in three-dimensional culture (3DC) via induction of luminal apoptosis in HCT116 cell spheroids. In this study, we showed that a novel compound, caffeic acid-adducted resveratrol, has a stronger inhibitory effect on the growth of HCT116 cell spheroids in 3DC than resveratrol. It showed almost the same inhibitory efficacy as 5-fluorouracil, a conventional anticancer drug. We further showed that the resveratrol derivative did not affect the growth of HKe3 cell spheroids derived from HCT116 cells by disruption of the activating mutant KRAS gene. These results suggest that the resveratrol derivative inhibits the growth of HCT116 cell spheroids via inhibition of an oncogenic KRAS-mediated signaling pathway.

Changes in content of triterpenoids and polysaccharides in Ganoderma lingzhi at different growth stages

Ganoderma lingzhi is a traditional medicinal mushroom, and its extract contains many bioactive compounds. Triterpenoids and polysaccharides are the primary bioactive components that contribute to its medicinal properties. In this study, we quantified 18 triterpenoids, total triterpenoid content and total polysaccharide content in the ethanol and water extracts of G. lingzhi at different growth stages. Triterpenoids were quantified by liquid chromatograph–tandem mass spectrometry in the multiple-reaction-monitoring mode. Total triterpenoid and total polysaccharide content were determined by colorimetric analysis. The results indicated that the fruit bodies at an early growth stage had a higher content of ganoderic acid A, C2, I and LM2, as well as of ganoderenic acid C and D, than those at a later growth stage. In contrast, ganoderic acid K, TN and T–Q contents were higher in mature fruit bodies (maturation stage). The highest total triterpenoid and total polysaccharide contents were found in fruit bodies before maturity (stipe elongation stage or early stage of pileus formation). Our results provide information which will contribute to the establishment of an efficient cultivation system for G. lingzhi with a higher content of triterpenoids.

An LC-MS/MS-SRM Method for Simultaneous Quantification of Four Representative Organosulfur Compounds in Garlic Products

The quantitative analysis of organosulfur compounds is important for the quality control of various garlic products along with studying their molecular functionality and nutraceutical properties. In this study, a liquid chromatography-tandem mass spectrometry-selected reaction monitoring (LC-MS/MS-SRM) method with electrospray ionization detection was developed and validated for the rapid, simultaneous quantification of four representative organosulfur compounds in garlic: alliin, S-allyl-L-cysteine, γ-glutamyl-S-allyl-L-cysteine, and allicin. Stable SRM transitions were achieved for these compounds under optimized conditions, and the linear range extended from 1 to 2000xa0ng/mL. The limits of detection and quantification ranged from 0.003 to 0.058xa0ng/mL and from 0.01 to 0.19xa0ng/mL, respectively. Excellent recovery and reproducibility at different spiking levels were achieved. The method was successfully applied to the simultaneous quantification of organosulfur compounds in fresh garlic samples. This highly selective and sensitive LC-MS/MS-SRM method is expected to be a useful tool for studying molecular functionality and the quality control of garlic products.