New glycosides from the twigs and leaves of Rhododendron latoucheae.

Six new glycosides (1-6), together with three known ones, were isolated from the twigs and leaves of Rhododendron latoucheae. Their structures were elucidated based on the spectroscopic data, including infrared spectrometry, mass spectrometry, and nuclear magnetic resonance experiments, along with Mosher's method. In addition, all compounds were tested their antiviral (herpes simplex virus-1 and influenza A/95-359) activities.

Minor Nortriterpenoids from the Twigs and Leaves of Rhododendron latoucheae.

A hyphenated NMR technique (analytical HPLC with a DAD connected to MS, SPE, and NMR) has proven effective for the full structural analysis and identification of minor natural products in complex mixtures. Application of this hyphenated technique to the CH2Cl2-soluble fraction of Rhododendron latoucheae led to the identification of 15 new minor ursane-type 28-nortriterpenoids (1-15). Compounds 1 and 12 inhibited HSV-1 with IC50 values of 6.4 and 0.4 µM, respectively.

[Chemical constituents from roots of Pieris formosa and their bioactivity].

By the means of chromatographic methods and spectroscopic evidences, 7 diterpenoids were isolated and identified from the roots of Pieris formosa. These known compounds are elucidated as secorhodomollolide C(1), pierisoid B (2), secorhodomollolide B (3), secorhodomollolide A (4), pierisformotoxin G (5), pierisformotoxin B (6) and pierisformotoxin A (7). Compounds 3, 4 were obtained from this plant for the first time. The analgesic activities of compounds 1-7 were evaluated using an acetic acidinduced writhing test in mice. Compounds 3, 4, 6, and 7 exhibited significant analgesic activity at 5 mg·kg;⁻ (ip) compared to vehicle-injected mice (P<0.05). The writhe inhibition rates of compounds 3, 4, 6 and 7 at 5 mg·kg⁻¹ (ip) were 41.3%, 39.4%, 38.6% and 37.5%, respectively.

[Chemical constituents from Vaccinium bracteatum].

The chemical constituents of Vaccinium bracteatum were studied by means of macroporous resin, ODS column chromatography and preparative HPLC. Eleven compounds were isolated from this plant. By using ESI-MS and NMR, the structures of the eleven compounds were determined as 10-O-trans-p-coumaroyl-6alpha-hydroxyl-dihydromonotropein (1), 10-O-cis-p-coumaroyl -6alpha-hydroxyl-dihydromonotropein (2), vaccinoside (3), 10-O-cis-p-coumaroyl monotropein (4), isolariciresinol-9-O-beta-D-xyloside (5), tectoridin (6), vicenin-3 (7), quercetin-3-O-alpha-L-rhamnoside (8), quercetin-3-O-alpha-L-arabinopyranoside (9), quercetin-3-O-beta-D-galactopyranoside (10), and quercetin-3-O-beta-D-glucuronide (11), respectively. Compounds 1 and 2 are new, and compounds 4, 6 and 7 are isolated from the genus Vaccinium for the first time.

[Chemical constituents from roots of Illicium majus].

Ten compounds, including seven sesquiterpenes, two phenols and one phenylpropanoid, were isolated from the roots of Illicium majus by means of silica gel, ODS, Sephadex LH-20, and preparative HPLC. On analysis of MS and NMR spectroscopic data , their structures were established as cycloparviflorolide (1), cycloparvifloralone (2), tashironin (3), tashironin A (4), anislactone A(5), anislactone B (6), pseudomajucin (7), syringaldehyde (8), methyl-4-hydroxy-3, 5-dimethoxybenzoate (9), and (E)-3-methoxy-4,5-methylenedioxycinnamic alchol (10), respectively. Compounds 1-4 and 8-10 were first isolated from this plant. In the in vitro assays, at a concentration of 1.0 x 10(-5) mol x L(-1), compounds 5 and 6 were active against LPS induced NO production in microglia with a inhibition rate of 75.31% and 53.7%, respectively.

Diverse epoxy grayanane diterpenoids with analgesic activity from the roots of Pieris formosa.

In our on-going study to investigate components with analgesic activity, eight new grayanane diterpenoids, epoxypieristoxins A-H (1-8), along with one known compound (9) were isolated from the roots of Pieris formosa. Their structures with absolute configurations were characterized by a series of spectroscopic methods and X-ray diffraction. Notably, compounds 1-5 represented the first example of natural grayanane diterpenoids possessed a 10,14-epoxy group. Whereas, compounds 6-7 were the first example of grayanane diterpenoid with a 7,10-epoxy group. Biological assays showed that compounds 1-3 and 5-8 displayed significant analgesic activity at a dose of 5.0 mg/kg (ip) compared to the vehicle tests (p < .05).

Pierisketolide A and Pierisketones B and C, Three Diterpenes with an Unusual Carbon Skeleton from the Roots of Pieris formosa.

Pierisketolide A (1) and pierisketones B and C (2 and 3), three diterpenes with an unusual A-homo-B-nor-ent-kaurane carbon skeleton, were isolated from the roots of Pieris formosa. Their structures were characterized by a series of spectroscopic methods, X-ray diffraction, and electronic circular dichroism (ECD). Pierisketolide A (1) exhibited an analgesic effect with a 45% writhe inhibition rate at a dose of 10.0 mg/kg. The plausible biosynthetic pathways of 1-3 are proposed.

Rhodoterpenoids A‒C, Three New Rearranged Triterpenoids from Rhododendron latoucheae by HPLC‒MS‒SPE‒NMR.

Rhodoterpenoids A‒C (1‒3), three new rearranged triterpenoids, together with one new biogenetically related compound, rhodoterpenoid D (4), were isolated and efficiently elucidated from Rhododendron latoucheae by high-performance liquid chromatography-mass spectrometry-solid-phase extraction-nuclear magnetic resonance (HPLC‒MS‒SPE‒NMR). Compounds 1 and 2 possess an unprecedented skeleton with a 5/7/6/6/6-fused pentacyclic ring system, while compound 3 contains a unique 6/7/6/6/6-fused pentacyclic carbon backbone. Their structures were determined by extensive spectroscopic methods and electronic circular dichroism (ECD) analyses. Plausible biogenetic pathways for 1‒4 were proposed. Compounds 1 and 4 showed potential activity against herpes simplex virus 1 (HSV-1) with IC50 values of 8.62 and 6.87 µM, respectively.