Anonazepine, a new alkaloid from the leaves of Annona muricata (Annonaceae).

From the CHCl3-soluble extract of Annona muricata L. (Annonaceae) leaves, one new 3-benzazepine-type alkaloid, anonazepine (1), and four known aporphine-type alkaloids, (+)-laurotetanine (2), (+)-norglaucine (3), (-)-xylopine (4), and lanuginosine (5), were isolated. Except for (-)-xylopine (4), these remaining known alkaloids were first reported in A. muricata. The structures of the isolated alkaloids were established by 1D and 2D NMR spectroscopy and MS, as well as comparison with literature data. The new 3-benzazepine-type alkaloid existed in an inseparable mixture of two equilibrium conformers. Its absolute configuration was determined based on comparing their experimental and calculated ECD data. The anti-inflammatory activity of the isolated alkaloids was investigated, but none of the alkaloids showed a significant result.

A new lignan from the stems of Buchanania lucida Blume (Anacardiaceae).

From the EtOAc-soluble extract of the stems of Buchanania lucida, one new lignan, (+)-(8S,8'S)-5'-methoxy-4,4'-di-O-methylsecoisolariciresinol (1), together with five known compounds (2-6) were isolated. Their structures were elucidated on the basis of NMR spectroscopic interpretation. The absolute configuration of 1 was determined based on the Cotton effects in the ECD spectrum. In the tyrosinase inhibitory activity test, p-hydroxybenzoic acid (6) showed the strong effect, with an IC50 value of 9.35 µM.

A new 8,3'-neolignan from Solanum procumbens Lour.

The phytochemical investigation of the EtOAc-soluble fraction of the aerial parts of Solanum procumbens Lour. has been carried out to obtain seven compounds, including a new 8,3'-neolignan named solacanin A (1). Their chemical structures were elucidated based on the spectroscopic data interpretation. All isolated compounds were tested for their α-glucosidase inhibitory activity. Compounds 1 and 3-6 showed inhibitory activity with IC50 values of 221.5, 18.9, 6.0, 104.1, and 219.7 µM, respectively.[Formula: see text].

Two new derivatives of 8-prenyl-5,7-dihydroxycoumarin from the stems of Streblus ilicifolius (S.Vidal) Corn.

From the EtOAc-soluble extract of the stems of Streblus ilicifolius (Moraceae), two new secondary metabolites named strebluses A (1) and B (2) were isolated. Their chemical structures have been concluded based on the chemical derivatisation and the spectroscopic interpretation. All compounds have been tested for their tyrosinase inhibitory activity. They showed weaker inhibitory activity than that of kojic acid (IC50, 44.6 µM).[Formula: see text].

δ-Tocopherol derivatives from the leaves of Muntingia calabura L.

From an ethyl acetate-soluble fraction of the leaves of Muntingia calabura, one new trimeric δ-tocopherol derivative named as tocomuntin A (1), together with three known δ-tocopherol derivatives (2-4) were isolated. Their structures were elucidated based on the interpretation of NMR and MS spectroscopic data. In this work, δ-tocopherol (3) was found to have α-glucosidase inhibitory activity for the first time (IC50, 47.3 µM).

A new diphenylheptanoid from the rhizomes of Curcuma zedoaria.

A phytochemical investigation of the rhizomes of Curcuma zedoaria was carried out, leading to the isolation of a new diphenylheptanoid, zedoaroxane A (1), together with four known compounds (2-5). Their structures were elucidated based on NMR spectroscopic data. All isolated compounds possessed α-glucosidase inhibitory activity, with the IC50 values ranging from 35.2 to 89.0 µM, more potent than that of the positive control acarbose (IC50, 214.5 µM).

Pipercyclobutanamide D, a new member of the cyclobutanamide-type alkaloid, from the roots of Piper nigrum.

From the EtOH-soluble extract of the roots of Piper nigrum, one new dimeric alkamide, pipercyclobutanamide D (1) was isolated. Its structure was elucidated on the basis of NMR spectroscopic interpretation. The relative configuration of 1 was determined based on the NOESY analysis. Compound 1 showed α-glucosidase inhibitory activity with an IC50 value of 158.5 µM. In addition, compound 1 exhibited cytotoxicity against the MCF-7 and HepG2 cell lines with the IC50 values of 45.6 and 63.9 µM, respectively. Plausible biosynthetic pathway for the formation of 1 was proposed based on regioselective [2 + 2] cycloaddition reaction.

A new phenolic acid from the wood of Mangifera gedebe.

From the methanol extract of the wood of Mangifera gedebe (Anacardiaceae), we had isolated a new secondary metabolite named gedebic acid (1) and six known compounds (2-7). Their chemical structures were determined by spectroscopic methods as well as comparing with data in the literature. All compounds were tested for α-glucosidase inhibitory activity. Compounds 4-7 showed more potent inhibitory activity, with IC50 values ranging from 45.3 to 142.6 µM, than that of a positive control acarbose (IC50, 214.5 µM).

Constituents of the Rhizomes of Boesenbergia pandurata and Their Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Line.

Human pancreatic cancer cell lines have a remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions represents a novel antiausterity strategy in anticancer drug discovery. In this investigation, a methanol extract of the rhizomes of Boesenbergia pandurata showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC50 value of 6.6 µg/mL. Phytochemical investigation of this extract led to the isolation of 15 compounds, including eight new cyclohexene chalcones (1-8). The structures of the new compounds were elucidated by NMR spectroscopic data analysis. Among the isolated compounds obtained, isopanduratin A1 (14) and nicolaioidesin C (15) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC50 values of 1.0 and 0.84 µM, respectively.

Anti-cholinesterases and memory improving effects of Vietnamese Xylia xylocarpa.

BACKGROUND: Alzheimer's disease (AD) is the most common cause of dementia among the elderly and is characterized by loss of memory and other cognitive functions. An increase in AChE (a key enzyme in the cholinergic nervous system) levels around ß-amyloid plaques and neurofibrillary tangles is a common feature of AD neuropathology. Amnesic effects of scopolamine (acetylcholine receptor antagonist) can be investigated in various behavioral tests such as Morris water maze, object recognition, Y-maze, and passive avoidance. In the scope of this paper, we report the anti-AChE, anti-BChE properties of the isolated compound and the in vivo effects of the methanolic extract of Xylia xylocarpa (MEXX) on scopolamine-induced memory deficit. RESULTS: In further phytochemistry study, a new hopan-type triterpenoid, (3ß)-hopan-3-ol-28,22-olide (1), together with twenty known compounds were isolated (2-21). Compound 1, 2, 4, 5, 7-9, and 11-13 exhibited potent acetylcholinesterase (AChE) inhibitory activity in a concentration-dependent manner with IC50 values ranging from 54.4 to 94.6 µM. Compound 13 was also shown anti-butyrylcholinesterase (BChE) activity with an IC50 value of 42.7 µM. The Morris water Y-maze, Y-maze, and object recognition test were also carried out. CONCLUSIONS: It is noteworthy that MEXX is effective when administered orally to mice, experimental results are consistent with the traditional use of this medicinal plant species.

A New Cassane-type Diterpene from the Seed of Caesalpinia sappan.

Phytochemical investigation of the CH2Cl2 extract of the Vietnamese medicinal plant Caesalpinia sappan Linn resulted in the isolation of a new cassane-type diterpene named tomocin I (1). Its chemical structure was determined by NMR spectroscopic and mass spectrometric analysis.

α-Glucosidase inhibitors from the leaves of Embelia ribes.

A novel and rare 1,4-dehydrated ceramide, embelamide (1), and a new C-glycoalkaloid which is based on a ß-carboline ring system, 1-(2'-deoxy-α-d-ribopyranosyl)-ß-carboline (4), were isolated from the CHCl3 soluble fraction of the leaves of Embelia ribes (Myrsinaceae), together with thirteen known compounds (2-3, 5-15). Their structures were elucidated on the basis of spectroscopic data. Compounds 1, and 5-12 possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, and showed more potent inhibitory activity, with IC50 values ranging from 1.3 to 155.0 µM, than that of a positive control acarbose (IC50, 214.5 µM).

α-Glucosidase inhibitors from the stems of Embelia ribes.

From the ethyl acetate extract of the stems of Embelia ribes (Myrsinaceae), a new alkenylresorcinol, embeliphenol A (1), together with 11 known compounds have been isolated. Their structures were elucidated on the basis of spectroscopic data. All compounds possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, except for 2 and 9. Compounds 1, 3-6, 8, and 12 showed more potent inhibitory activity, with IC50 values ranging from 10.4 to 116.7 µM, than that of a positive control acarbose (IC50 , 214.5 µM).

Geranyl dihydrochalcones from Artocarpus altilis and their antiausteric activity.

Human pancreatic cancer cell lines have remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions is a novel antiausterity strategy in anticancer drug discovery. In this study, the methanolic extract of the leaves of Artocarpus altilis showed 100 % preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions at a concentration of 50 µg/mL. Further investigation of this extract led to the isolation of eight new geranylated dihydrochalcones named sakenins A-H (1-8) together with four known compounds (9-12). Among them, sakenins F (6) and H (8) were identified as potent preferentially cytotoxic candidates with PC50 values of 8.0 µM and 11.1 µM, respectively.

Cleistanthane diterpenes from the seed of Caesalpinia sappan and their antiausterity activity against PANC-1 human pancreatic cancer cell line.

Three new cleistanthane diterpenes named tomocinon (1), tomocinol A (2), and tomocinol B (3), were isolated from the EtOAc extract of the seed of Caesalpinia sappan. Their structures were determined by extensive NMR spectroscopic analysis. The absolute stereochemistry of tomocinon (1) has been established by CD spectroscopic analysis. Cleistanthane diterpenes (1-3) represents the novel class of antiausterity agents having preferential cytotoxicity against PANC-1 human pancreatic cancer cell line under nutrient deprived condition with PC50 value of 34.7 µM, 42.4 µM and 39.4 µM, respectively.