Effects of Hippeastrum reticulatum on memory, spatial learning and object recognition in a scopolamine-induced animal model of Alzheimer's disease.

CONTEXT: The methanol extracts from Hippeastrum reticulatum (L'Hér.) Herb. (Amaryllidaceae) (HR) display acetylcholinesterase inhibitory (AChEI) activity. OBJECTIVE: AChEI of alkaloids isolated from HR bulbs and the ameliorating effects of the alkaloid fraction (AHR) on memory and cognitive dysfunction in scopolamine-treated mice were investigated. MATERIALS AND METHODS: Alkaloids were isolated by column chromatography and identified by spectroscopy. AChEI was evaluated using the modified Ellman's method. Sixty Swiss male mice were randomly divided into six groups, received samples for 15 days. Normal group received saline, scopolamine-treated group scopolamine (1.5 mg/kg, intraperitoneal injection). Test groups received AHR (5, 10 and 15 mg/kg, per os) and positive control group donepezil (5 mg/kg, per os), administered 1 h before the test, scopolamine was injected 30 min prior to testing. The cognitive-enhancing activity of AHR against scopolamine-induced memory impairments was investigated using Y-maze, the novel object recognition test (NORT) and the Morris water maze (MWM) test. RESULTS: Seven alkaloids were isolated for the first time from the genus Hippeastrum: trans-dihydronarciclasine (1), N-chloromethylnarcissidinium (2), narciprimin (3), narciclasine-4-O-ß-d-xylopyranoside (4), N-methyltyramine (5), 3ß,11α-dihydroxy-1,2-dehydrocrinane (6) and brunsvigine (7); three are new compounds (2, 5, 6). Among them, 2-3 and 5-6 showed AChEI in vitro with IC50 values of 29.1, 46.4, 70.1 and 104.5 µg/mL, respectively. The anti-AChEI of 2, 5 and 6 are reported for the first time. In in vivo test, AHR (15 mg/kg) significantly increased in spontaneous alternation performance in the Y-maze test (p < 0.01), it significantly increased the time spent exploring the novel object (p < 0.05) comparison with scopolamine-treated group. The administration of AHR at doses 10 and 15 mg/kg significantly decreased escapes latency and swimming distance to the platform on day 6 compared to these in day 1 (p < 0.01 and p < 0.05, respectively). CONCLUSIONS: AHR could be a potential candidate of future trials for treatment of memory and cognitive dysfunction in Alzheimer's disease.

Chemical composition and anti-inflammatory activity of the essential oil from the leaves of Limnocitrus littoralis (Miq.) Swingle from Vietnam.

The oil from the leaves of Limnocitrus littoralis (Miq.) Swingle was obtained by hydrodistillation and investigated by gas chromatography combined with mass spectrometry (GC/MS), the anti-inflammatory effect of the oil was examined on a LPS-induced RAW264.7 cells. An aggregate of forty components were identified, representing 93.0% of the oil. This oil was subjugated by monoterpene hydrocarbons (27.7%), sesquiterpene hydrocarbons (32.3%) and oxygenated sesquiterpenes (4.6%). The significant constituents of L. littoralis essential oil were determined as follows; myrcene (24.9%), γ-muurolene (11.0%), and oleic acid (10.3%). The essential oil of L. littoralis showed activity against the nitric oxide (NO) generation with the IC50 value to 12.50 ± 1.19 µg/L. The anti-inflammatory effect of essential oil from the leaves of L. littoralis is reported for the first time.

Flavonoids and alkaloids from the rhizomes of Zephyranthes ajax Hort. and their cytotoxicity.

A new flavanol derivative, (2R,3R)-3-acetoxy-7-hydroxy-3',4'-methylenedioxyflavan (1), was co-isolated from the rhizomes of Zephyranthes ajax Hort. with the following seven known compounds: 7-hydroxyflavan (2), 7,4'-dihydroxyflavan (3), 7,4'-dihydroxy-8-methylflavan (4), 7,3'-dihydroxy-4'-methoxyflavan (5), 5,4'-dihydroxy-7-methoxy-6-methylflavan (6), 7-hydroxy-3',4'-methylenedioxyflavanone (7) and haemanthamine (8). Their structures were elucidated by combining 1D-/2D-NMR, CD, UV and HRESIMS data, and comparisons with reported data in literature were made. Among these known compounds, 2, 3, 4, 6 and 7 were isolated from the genus Zephyranthes for the first time. In addition, the cytotoxicity assay indicated that compound 8 has potent cytotoxic activity against human hepatocellular carcinoma (the HepG2 cell line), human lung carcinoma (the SK-LU-1 cell line), human carcinoma in the mouth (the KB cell line), human colon carcinoma (the SW480 cell line) and human stomach gastric adenocarcinoma (the AGS cell line), with IC50 values ranging from 4.4 to 11.3 µM. This is the first study reporting the cytotoxicity of compound 8 against the SK-LU-1 cancer cell lines.

Three new steroidal saponins from Aspidistra letreae plants and their cytotoxic activities.

Three new steroidal saponins, aspiletreins A-C (1-3), together with 2H-chromen-2-one (4), and α-tocopherol (5), were isolated from whole Aspidistra letreae plants collected in Vietnam. Their structures were elucidated by a combination of spectroscopic analyses, including 1D- and 2D-NMR, IR, and HRESIMS, and by comparison with the reported data in the literature. Compounds 1-3 exhibited moderate cytotoxicities against the LU-1, HeLa, MDA-MB-231, HepG2, and MKN-7 human cancer cell lines, with IC50 values ranging from 7.69 ± 0.40 to 20.46 ± 3.11 µM.