排序方式: 共有42条查询结果,搜索用时 15 毫秒
31.
Atta-ur-Rahman Feroz F Zaheer-ul-Haq Nawaz SA Khan MR Choudhary MI 《Natural product research》2003,17(4):235-241
Two new steroidal alkaloids, salonine-A [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-5alpha-pregn-14-en-2beta,4beta-diol] (1), and salonine-B [(20S)-20-(N,N-dimethylamino)-3beta-methoxy-pregn-5,16-diene] (2), were isolated from the MeOH extract of Sarcococca saligna, along with a known base, alkaloid-C (3). Their structures were elucidated on the basis of spectroscopic methods. All three compounds were found to be cholinesterase inhibitors. 相似文献
32.
Atta-ur-Rahman Choudhary MI Hayat S Khan AM Ahmed A 《Chemical & pharmaceutical bulletin》2001,49(1):105-107
Two new aurones, 4'-chloro-2-hydroxyaurone (1) and 4'-chloroaurone (2) were isolated from Spatoglossum variabile. The structures of these compounds were elucidated by modern spectroscopic techniques. 相似文献
33.
Tsuda Y Atta-ur-Rahman Akhtar MN Sener B Parvez M Sashida Y Mimaki Y Mizuno M 《Natural product research》2004,18(3):205-209
The structure of a new crystalline base (melting point (mp) 167-169 degrees C) obtained from Fritillaria imperialis was elucidated as (20R, 25R)-5alpha,17beta-cevanine-3beta,6beta-diol, X-ray diffraction analysis of the mono-hydrate. The base was found to be identical with persicanidine B and also with harepermine. 相似文献
34.
Choudhary MI Yousuf S Nawaz SA Ahmed S Atta-ur-Rahman 《Chemical & pharmaceutical bulletin》2004,52(11):1358-1361
A total of two new (1, 2) and four known (3-6) withanolides were isolated from the whole plant of Withania somnifera. Their structures were elucidated on the basis of spectroscopic techniques and were characterized as 6alpha,7alpha-epoxy-3beta,5alpha,20beta-trihydroxy-1-oxowitha-24-enolide (1), 5beta,6beta-epoxy-4beta,17alpha,27-trihydroxy-1-oxowitha-2,24-dienolide (2), withaferin-A (3), 2,3-dihydrowithaferin-A (4), 6alpha,7alpha-epoxy-5alpha,20beta-dihydroxy-1-oxowitha-2,24-dienolide (5), and 5beta,6beta-epoxy-4beta-hydroxy-1-oxowitha-2,14,24-trienolide (6), respectively. Compounds 2, 3, 5, and 6 displayed inhibitory potential against butyrylcholinesterase, but only compounds 3, 4, and 6 were found to be active against acetylcholinesterase. 相似文献
35.
Sultankhodzhaev MN Khan MT Moin M Choudhary MI Atta-ur-Rahman 《Natural product research》2005,19(5):517-522
In the present article, tyrosinase inhibition studies on fifteen diterpenoid alkaloids, with lycoctonine skeleton, and their semisynthetic derivatives 1-15 and six napelline-type compounds 16-21 are discussed. Their structure-activity relationship for tyrosinase inhibition is also discussed. These activities were compared with two referenced tyrosinase inhibitors, kojic acid and L-mimosine. The study showed that lappaconitine HBr (1) is the most potent member of the series (IC50 = 13.30 microM). 相似文献
36.
Two new rearranged taxoids from Taxus wallichiana ZUCC 总被引:2,自引:0,他引:2
Choudhary MI Khan AM Habib-ur-Rehman Atta-ur-Rahman Ashraf M 《Chemical & pharmaceutical bulletin》2002,50(11):1488-1490
Two new rearranged taxane diterpenoids, 5alpha,7beta,10beta,13alpha-tetrahydroxy-2alpha,9alpha,15-triacetoxy-11(15-->1)-abeo-taxa-4(20), 11-diene (1) and 5alpha,9alpha,10beta,13alpha-tetraacetoxy-15-hydroxy-11(15-->1)-abeo-taxa-4(20), 11-diene (2) have been isolated from the barks of Taxus wallichiana. The structures of these compounds have been confirmed by modern spectroscopic techniques. 相似文献
37.
Choudhary MI Ismail M Ali Z Shaari K Lajis NH Atta-ur-Rahman 《Natural product communications》2010,5(11):1747-1750
Phytochemical investigations of the stems of Tinospora crispa led to the isolation of one new aporphine alkaloid, N-formylasimilobine 2-O-beta-D-glucopyranoside (1), along with six known alkaloids, N-formylasimilobine 2-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranoside (2) (tinoscorside A), N-formylanonaine (3), N-formyldehydroanonaine (4), N-formylnomuciferine (5), N-demethyl-N-formyldehydronornuciferine (6), magnoflorine (7), paprazine (8), N-trans-feruloyltyramine (9), and cytidine (10). The structure of new compound 1 was deduced on the basis of spectroscopic data. 相似文献
38.
39.
Amjad Hussain Achyut Adhikari Syed Abdulmajid Ayatollahi Atta-ur-Rahman 《Natural product research》2016,30(13):1511-1516
A new adduct of abietane-type diterpene, salvialeriicone (1), was isolated from Salvia leriifolia Benth., along with a new chemical entity nor-abietane diterpene, 2-isopropyl-8,8-dimethyl-7,8-dihydrophenanthrene-1,4,5(6H)-trione (2). Their structures were determined using mass spectrometry, and 1D- and 2D-NMR spectroscopy. 相似文献
40.
Choudhary MI Begum A Abbaskhan A Ajaz A Shafique-ur-Rehman Atta-ur-Rahman 《Chemical & pharmaceutical bulletin》2005,53(11):1469-1471
A phytochemical investigation on the aerial parts of Lindelofia stylosa has resulted in the isolation of seven phenyl propanoids. This includes three analogs of lithospermic acid, along with rosmarinic acid and its ester derivatives. Compound 1 was identified as a new natural product. These compounds were studied for their antioxidant properties. 相似文献