[Studies on medical resources. XXXIV. The constituents of genus Eurya. (1). E. japonica Thunb. and E. emarginata Makino (author's transl)]

Three new glycosides from the stems of Eurya chinensis R. Br

Two new phenolic glycosides (1 and 2), one known analogue (3), along with a new diterpene glucoside (4) were obtained from ethanolic extract of the stems of Eurya chinensis R. Br. The structures of these isolated compounds were identified by extensive analysis of HRESIMS and NMR spectroscopic data. The cytotoxicities of these compounds were evaluated on MCF-7, A549, HepG2, CaCo2 and 5-8 F cell lines by MTT method, but no obvious activities were observed.

Sexual Differences in Eurya loquaiana Dunn Floral Scent and How Pollinators Respond

Eurya plants are usually dioecious or subdioecious with small fragrant flowers. Here, we investigate the floral scent components of the subdioecious species Eurya loquaiana Dunn and how floral scent affects pollinators. Headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) was used to compare the floral scents of male, female, and hermaphrodite flowers. We also test whether differences in floral scent affect the foraging behaviors of pollinators and describe the flower morphological traits of the three sexes. Twenty-eight floral scent compounds were tentatively identified, and four monoterpenoids were tentatively identified as the most abundant compounds: linalool oxide (pyranoid), linalool, lilac aldehyde, and linalool oxide (furanoid). There were floral scent differences among the sex types, and male flowers were more attractive to pollinators in the wild, even when visual factors were excluded, indicating that pollinators likely distinguish sexual differences by floral scent. In the competition for pollinators, the advantage that male flowers have over female and hermaphrodite flowers can likely be accounted for the differences in floral scent and display size.

Two new ent-kaurane diterpenes from the stems of Eurya chinensis

Two new ent-kaurane diterpenes (1-2), together with five known analogs, were isolated from the stems of Eurya chinensis. The structures of new compounds were established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 3 exhibited noticeable anti-inflammatory activity as denoted by inhibiting LPS-induced nitric oxide (NO) production in RAW264.7 cells with an IC₅₀ value of 7.82 μM. Compound 4 showed potent cytotoxic activity against human cancer cell lines NCI-H46, HepG2 and SW480 with IC₅₀ values ranging from 7.45 to 8.54 μM.

A new ent-kaurane diterpene derivative from the stems of Eurya chinensis R.Br

One new ent-kaurane diterpene derivative (1), along with four known diterpenes, was isolated from the stems of Eurya chinensis R.Br. The structure of the new compound was established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 1 showed moderate anti-inflammatory activities with IC₅₀ value of 8.12 μM. This is the first example of diterpenoids with 4-hydroxy-4-(2-hydroxyethyl)-1-hydroxyl-cyclohexanoyl substituent.

Anti-inflammatory and antimicrobial coumarins from the stems of Eurya chinensis

Two new coumarins, named (±)-euryacoumarin A (1) and 6-demethylobtusinin (2), and one new natural coumarin, named euryacoumarin B (3), along with two known compounds, scopoletin (4) and obtusinol (5), were isolated from the stems of Eurya chinensis. Their structures were elucidated by means of extensive spectroscopic methods and comparison with data reported in the literatures. Compound 1 exhibited significant inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 cells with IC₅₀ value of 35.64 ± 1.73 μM, and showed marginal antibacterial activities against Bacillus subtilis and B. cereus with MIC values of 50.59 ± 2.12 and 35.42 ± 0.96 μM, respectively.

Euryachins A and B, a new type of diterpenoids from Eurya chinensis with potent NO production inhibitory activity

Euryachins A (1) and B (2), new typediterpenoid euryamanes, were isolated from the branches of Eurya chinensis. The absolute configuration of 1 was determined by single-crystal X-ray diffraction. Both 1 and 2 exhibited significant NO production inhibitory activity.

Chrysoeriol isolated from the leaves of Eurya ciliata stimulates proliferation and differentiation of osteoblastic MC3T3-E1 cells

Chrysoeriol (1) was isolated as the main constituent from the methanol extract of the dried leaves of Eurya ciliata Merr. To investigate the bioactivities of 1 on bone metabolism, its effects on the function of osteoblastic MC3T3-E1 cells were studied. Compound 1 significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase activity, collagen content, and nodule mineralization in the cells (P < 0.05). Our data indicate that the enhancement of osteoblast function by 1 may be useful in the prevention of osteoporosis.

Mutagenicities of 61 flavonoids and 11 related compounds

The mutagenicities of 61 flavonoids (naturally occurring flavonoid aglycones and flavonal glycosides and synthetic flavonoids) and those of 11 compounds structurally related to flavonoids were tested with Salmonella typhimurium strains TA100 and TA98. Among the 22 flavone derivatives tested, only wogonin was strongly mutagenic, while five derivatives, apigenin triacetate, acacetin, chrysoeriol, pedalitin, and pedalitin tetraacetate, were only weakly mutagenic. Two bisflavonyl derivatives, neither of which has a 3-hydroxyl group, were not mutagenic. Of the 16 flavonol derivatives tested, all except 3-hydroxyflavone and the tetra- and penta-methyl ethers of quercetin were mutagenic. Of the five flavanone derivatives tested, only 7,4-dihydroxyflavanone was mutagenic, showing weak activity. Of the four flavanolol derivatives tested, hydrorobinetin and taxifolin were weakly mutagenic. Of the six isoflavone derivatives tested, tectorigenin was weakly mutagenic. Of the 11 compounds in the miscellaneous group structurally related to flavonoids, only isoliquiritigenin was mutagenic, showing weak activity. For the emergence of strong mutagenicity, the double bond between positions 2 and 3 and the hydroxyl group at position 3 are required, except in wogonin, which does not have a hydroxyl group at position 3 but is strongly mutagenic to TA100. The 3-O-acetyl ester of flavonol, quercetin, was mutagenic with S9 mix, but 3-O-methyl ethers were not. Six flavonol glycosides, three quercetin glycosides and three kaempferol glycosides were mutagenic after preincubation with "hesperidinase," a crude extract of Aspergillus niger. Of 66 flavonoid agylcones and compounds structurally related to flavonoids, quercetin was the strongest mutagen. The carcinogenicity of this compound should be clarified because it is ubiquitously found in vegetables.