ent-kaurane diterpenoids from Annona glabra

Three new kaurane diterpenoids, annoglabasin C (16alpha-acetoxy-ent-kauran-19-oic acid-17-methyl ester) (1), annoglabasin D (16alpha-acetoxy-ent-kauran-19-al-17-methyl ester) (2), and annoglabasin E (16alpha-hydro-19-ol-ent-kauran-17-oic acid) (3), and a new norkaurane diterpenoid, annoglabasin F (16alpha-acetoxy-19-nor-ent-kauran-4alpha-ol-17-methyl ester) (4), along with 13 known kaurane derivatives were isolated from the stems of Annona glabra. 16alpha-Methoxy-ent-kauran-19-oic acid (5) and 16alpha-hydro-ent-kauran-17,19-dimethyl ester (6) were obtained for the first time as natural products. The structures of compounds 1-6 were characterized by spectral analysis.     

Dimeric ent-kaurane diterpenoids from Isodon excisus

Five new dimeric ent-kauranoids, biexcisusins A-E (1-5), were isolated from the aerial parts of Isodon excisus. The structures and relative configurations of these compounds were determined on the basis of spectroscopic data interpretation. Of these, biexcisusins C-E (3-5) are dimeric ent-kaurane diterpenoids exhibiting an unprecedented linkage through a nine-membered lactone ring between two ent-kaurane subunits. Compounds 1-5 showed no inhibitory effects on the LPS-induced production of nitric oxide in murine macrophage RAW264.7 cells, up to a dose of 50 μM.     

ent-kaurane diterpenoids from Isodon lungshengensis.

Six new ent-kaurane diterpenoids, lungshengenins B-G (1-6), together with three known diterpenoids, lungshengenin A (7), inflexin (8), and lushanrubescinsin C (9), were isolated from the leaves and tender branches of Isodon lungshengensis. Their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. Lungshengenins A (7), C (2), and G (6) were cytotoxic toward K562 cells, having IC(50) values equal to or less than 10 microg/mL.     

ent-kaurane diterpenoids from the liverwort Jungermannia atrobrunnea

Three new rearranged ent-kaurane-type diterpenoids (1-3) and seven new ent-kaurane-type diterpenoids (4-10) have been isolated from the liverwort Jungermannia atrobrunnea. Their structures were determined by extensive spectroscopic techniques and X-ray crystallographic analysis. The absolute configurations of these compounds were clarified by CD spectroscopic studies. Compound 1 is the first example of a rearranged ent-kaurane diterpenoid possessing a peroxide bridge.     

冬凌草中三个新的对映-贝壳杉烷二萜及其细胞毒活性

目的：研究产自湖北省建始县的冬凌草（1sodon rubescens）地上部分的化学成分;方法：利用正反相硅胶柱色谱、高效液相色谱等现代分离技术进行分离;通过IR,UVMS,NMR等波谱方法鉴定了化合物结构式;对化合物1进行了单晶X-射线衍射分析,确定了其绝对构型;化合物1_9进行了对HL-60,SMMC-7721,A-549,MCF-7和SW-480细胞株的体外细胞毒活性测定：结果：分离鉴定了8个对映-贝壳杉烷二萜和1个对映-赤霉烷二萜;结论：建始冬凌草庚素-壬素（1-3）为新化合物,其中2是一个少见的、3位为半缩酮结构的3,20-环氧-对映-贝壳杉烷二萜;所有受试化合物中,4和5对某些细胞株表现出一定的体外抗增殖活性。     

Anti-tumor activity of Annona squamosa seeds extract containing annonaceous acetogenin compounds

Ethnopharmacological relevance

Seeds of Annona squamosa L. have been used in the south of China as a folk remedy to treat “malignant sores” (cancer).

Aim of the study

To investigate the chemical constituents and the anti-tumor activity of the standardized A. squamosa seeds extract in vitro and in vivo.

Materials and methods

Annonaceous acetogenin profiles of the standardized extract were determined by using Fourier transform infrared (FT-IR) and high performance liquid chromatography (HPLC) techniques. The anti-tumor activity of the extract was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cytotoxicity in vitro and H₂₂ hepatoma cells transplantation tumor model in vivo.

Results

The FT-IR spectroscopy showed the presence of annonaceous acetogenin compounds in the extract. Two major annonaceous acetogenins: 12, 15-cis-squamostatin-A and bullatacin were identified and quantified by HPLC. The seed extract showed significant anti-tumor activity against four human tumor cell lines, especially for MCF-7 (IC₅₀. 0.25 μg/ml) and Hep G2 (IC₅₀. 0.36 μg/ml) cells in vitro. The extract inhibited the growth of H₂₂ tumor cells in mice with a maximum inhibitory rate of 69.55% by oral administration.

Conclusion

A. squamosa seed extract showed significant anti-tumor activities against human hepatoma cells in vitro and in vivo, indicating a potential for developing the extract as a novel anti-liver cancer drug.     

Cytotoxic bistetrahydrofuran annonaceous acetogenins from the seeds of Annona squamosa

Three new bistetrahydrofuran annonaceous acetogenins (1-3) were isolated from a 95% EtOH extract of Annona squamosa seeds. Four known annonaceous acetogenins, uvarigrandin A (4), bullatacin (5), squamostatin-A (6), and squamostatin-D (7), were also isolated. Their structures were elucidated by spectroscopic analyses, and the absolute configurations of the carbinol centers of 1-3 were defined by application of the Mosher method. These compounds all exhibited significant cytotoxic activity in vitro against five human tumor cell lines.     

Hemiterpene glucosides with anti-platelet aggregation activities from Ilex pubescens

Two new hemiterpene glucosides named pubescenosides A and B were isolated from the root of Ilex pubescens. Their structures were elucidated on the basis of spectroscopic and chemical evidence as 2-(trans-caffeoyloxy)methyl-3-hydroxy-1-butene-4-O-beta-D-glucopyranoside and 2-hydroxymethyl-3-caffeoyloxy-1-butene-4-O-beta-D-glucopyranoside, respectively. Pharmacological investigation on pubescenosides A and B indicated that both possess potent anti-platelet aggregation activities.     

Samoquasine A, a benzoquinazoline alkaloid from the seeds of Annona squamosa

A benzooxyquinazoline alkaloid, samoquasine A (1), has been isolated from the seeds of Annona squamosa, and its structure was elucidated by spectroscopic and chemical methods.     

Antidiabetic activity of aqueous leaf extract of Annona squamosa in streptozotocin-nicotinamide type 2 diabetic rats

The claim by some tribal populations in parts of Northern India that the young leaves of the custard apple tree, Annona squamosa L. (Annonaceae) has antidiabetic properties was investigated. Diabetes mellitus was induced with streptozotocin-nicotinamide and graded doses of the aqueous leaf extracts were then administered in drinking water to normal and experimental diabetic rats for 12 days. Fasting plasma glucose levels, serum insulin levels, serum lipid profiles and changes in body weight were evaluated in normal rats while liver glycogen levels and pancreatic TBARS levels were evaluated additionally in diabetic rats. The diabetic groups treated with the aqueous leaf extract were compared with standard glibenclamide. The findings of the study support the antidiabetic claims of Annona squamosa.     

Mono-tetrahydrofuran annonaceous acetogenins from Annona squamosa as cytotoxic agents and calcium ion chelators

Eight new mono-tetrahydrofuran (THF)-type annonaceous acetogenins, squafosacins B, C, F, and G (1-4), squadiolins A-C (5-7), and cis-annotemoyin-1 (8), as well as eight known annonaceous acetogenins, glabranin, annotemoyins-1 and -2, bullatencin, cis-bullatencin, and uvariamicins-I, -II, and -III, were isolated from the seeds of Annona squamosa by HPLC. The structures of all new isolates were elucidated by using spectroscopic and chemical methods. Squadiolins A (5) and B (6) showed ng/mL potency against human Hep G2 hepatoma cells and significant cytotoxic activity against human MDA-MB-231 breast cancer cells. Squafosacin B (1) also exhibited significant cytotoxic activity against human Hep G2 and 3B hepatoma and MCF-7 breast cancer cells. In addition, the chelation of mono-THF acetogenins with calcium ions was investigated using isothermal titration calorimetry.     

番荔枝内生菌拟茎点霉B27中分离到的一个新十元大环内酯

目的：研究番荔枝内生真菌拟茎点霉B27的化学成分。方法：通过色谱层析柱对提取物进行分离纯化，并通过波谱解析（一维、二维的核磁共振谱和质谱）确定化合物的结构。结果：分离纯化得到5个化合物，鉴定为十元大环内酯phomolidec（1），1-甲基-8-羟基-9，10-蒽醌（2），1，8-双羟基-9，10-蒽醌（3），cytosporoneC（4）和Altiloxin A（5）。结论：化合物1是新化合物；化合物1-5首次从拟茎点霉属菌株中分离得到。     

New alkaloids from Annona purpurea

Three new alkaloids, promucosine (1), romucosine F (2), and romucosine G (3), along with 28 known compounds, were isolated from the MeOH extract of stems of Annona purpurea. The structures of 1-3 were determined on the basis of spectral data and chemical evidence.     

Clerodane diterpenoids with NGF-potentiating activity from Ptychopetalum olacoides

Four new clerodane-type diterpenoids, ptychonolide (1), 20-O-methylptychonal acetal (2), and an equilibrium mixture of ptychonal hemiacetal (3) and ptychonal (4), were isolated from the MeOH extract of the bark of a Brazilian plant, Ptychopetalum olacoides. The structure of 1 was elucidated as a clerodane-type diterpenoid on the basis of spectroscopic data, whereas 2 was assigned to an acetal derivative of 1. Compounds 3 and 4 existed as an equilibrium mixture. A mixture of compounds 3 and 4 was found to exhibit neurite outgrowth-promoting activities on NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10.0 microM.     

Cyclopeptides with anti-inflammatory activity from seeds of Annona montana

Four new cyclopeptides, cyclomontanins A-D (1- 4), annomuricatin C (5), and (+)-corytuberine were isolated from a methanol extract of Annona montana seeds. Their structures were elucidated by 2D NMR analysis, ESIMS/MS fragment evidence, and chemical means. The structure of 1 was confirmed by synthesis. Compounds 1, 3, and 4 exhibited anti-inflammatory activity in vitro using the J774.1 macrophage model.     

New diterpenoids from Viburnum awabuki

Eight new vibsane-type diterpenoids, vibsanins P-W (1-8), were isolated from the methanol extracts of the leaves and twigs of Viburnum awabuki. The structures were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.     

Toxicity testing of organic solvent extracts from Annona squamosa: Effects on rabbit eyes and ear skin

Some organic solvent extracts of seeds and leaves from Annona squamosa exhibit insecticidal activity. They were studied for the management of human lice. However, toxicological data of these extracts have not yet been widely reported. In this experiment, the extracts of active compounds of leaves and seeds from A. squamosa in four organic solvents, i.e. petroleum ether, ether, chloroform and ethanol were tested for toxicity to the eyes and ear skin of rabbits, using 1:10 (w/v) dilutions of dried extracts in propylene glycol as test substances. The results revealed that some extracts caused conjunctival redness, chemosis, rugged cornea, skin erythema and oedema. The organic solvent extracts that produced adverse effects on rabbit eyes were in the following order of severity: ether > petroleum ether > chloroform > ethanol, and those on rabbit ear skin were petroleum ether > ether > chloroform > ethanol. Ethanol extracts of leaves and seeds seemed to produce mildest toxicity to rabbit eyes and no toxicity to rabbit ear skin.     

New bis-secolabdane diterpenoids from Excoecaria agallocha

Two new bis-secolabdane diterpenoids, excoecarins R1 (1) and R2 (2), were isolated from the resinous wood of Excoecaria agallocha. The structures of 1 and 2 were established on the basis of spectroscopic data interpretation and chemical evidence.     

A pyrimidine-beta-carboline and other alkaloids from Annona foetida with antileishmanial activity

Bioassay-guided fractionation of the bark extract of Annona foetida afforded a new antileishmanial pyrimidine-beta-carboline alkaloid, N-hydroxyannomontine (1), together with the previously reported annomontine (2), O-methylmoschatoline (3), and liriodenine (4). The structure of compound 1 was established on the basis of extensive 1D and 2D NMR and MS analyses. This is the third reported pyrimidine-beta-carboline-type alkaloid and is particularly important for Annona genus chemotaxonomy. In addition, all compounds exhibit in vitro antileishmanial activity against promastigote forms of Leishmania braziliensis. Compounds 2 and 4 showed better activity than compounds 1 and 3 against L. braziliensis. Compound 2 was not active against L. guyanensis.     

Bullatacin, bullatacinone, and squamone, a new bioactive acetogenin, from the bark of Annona squamosa

Activity-directed fractionation of the stem bark of Annona squamosa, monitoring with brine shrimp lethality, led to the isolation of the highly bioactive acetogenins bullatacin [1] and bullatacinone [2], thus demonstrating a new abundant plant source for these potent compounds. A new keto-monotetrahydrofuran acetogenin with a ketolactone terminus, as first seen in bullatacinone [2], was also isolated, characterized by spectral analyses, and named squamone [3]. The cytotoxicities of 3 were increased significantly by reduction of the two keto groups to hydroxyls, and the tetrahydrosquamone [7] and bullatacinone [2] both showed selective cytotoxicities to MCF-7 human breast carcinoma. Liriodenine and (-)-kaur-16-en-19-oic acid were also isolated.