Muhammad Arfan

Antioxidant Activity of Mulberry Fruit Extracts

Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75–1.25 mmol Trolox/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) (EC50 from 48 μg/mL to 79 μg/mL), and reducing power assays. However, a stronger activity was noted for the SFEs obtained from Morus nigra fruits. These extracts also possessed the highest contents of total phenolics: 164 mg/g (methanolic SFE) and 173 mg/g (acetonic SFE). The presence of phenolic acids and flavonoids in the extracts was confirmed using HPLC method and chlorogenic acid and rutin were found as the dominant phenolic constituents in the SFEs.

Pistagremic acid, a glucosidase inhibitor from Pistacia integerrima.

Pistacia integerrima Stewart in traditionally used as folk remedy for various pathological conditions including diabetes. In order to identify the bioactive compound responsible for its folk use in diabetes, a phytochemical and biological study was conducted. Pistagremic acid (PA) was isolated from the dried galls extract of P. integerrima. Strong α-glucosidase inhibitory potential of PA was predicted using its molecular docking simulations against yeast α-glucosidase as a therapeutic target. Significant experimental α-glucosidase inhibitory activity of PA confirmed the computational predictions. PA showed potent enzyme inhibitory activity both against yeast (IC(50): 89.12±0.12μM) and rat intestinal (IC(50): 62.47±0.09μM) α-glucosidases. Interestingly, acarbose was found to be more than 12 times more potent an inhibitor against mammalian (rat intestinal) enzyme (having IC(50) value 62.47±0.09μM), as compared to the microbial (yeast) enzyme (with IC(50) value 780.21μM). Molecular binding mode was explored via molecular docking simulations, which revealed hydrogen bonding interactions between PA and important amino acid residues (Asp60, Arg69 and Asp 70 (3.11Å)), surrounding the catalytic site of the α-glucosidase. These interactions could be mainly responsible for their role in potent inhibitory activity of PA. PA has a strong potential to be further investigated as a new lead compound for better management of diabetes.

Anti-inflammatory xanthones from the twigs of Hypericum oblongifolium wall.

Two new xanthonolignoids, hypericorin A (1) and hypericorin B (2), along with five known new source compounds, a xanthonolignoid, kielcorin (3), 4-hydroxy-2,3-dimethoxyxanthone (4), 3,4,5-trihydroxyxanthone (5), 1,3-dihydroxy-5-methoxyxanthone ( 6) and 1,3,7-trihydroxyxanthone (7), were isolated from the stems (twigs) of Hypericum oblongifolium Wall. The structures of the new compounds were deduced on the basis of spectroscopic techniques (EI-MS, HREI-MS, (1)H NMR, (13)C NMR, HMQC, HMBC, and NOESY). We also report herein for the first time the single crystal X-ray structure of compound 6. Compounds 1- 7 were screened for their IN VITRO anti-inflammatory (respiratory burst) inhibiting activities using isolated human neutrophils; compounds 1, 2, 3, 5, and 7 showed significant activities (IC (50) = 816.23 ± 73.30, 985.20 ± 55.80, 965.21 ± 65.80, 907.20 ± 50.80, 975.20 ± 81.10 µM, respectively), compound 6 showed moderate activity (IC (50) = 2500.85 ± 50.50 µM), while compound 4 was totally inactive at 1000 µg/mL as compared to the positive control used, indomethacin (IC (50) = 757.99 ± 5.90 µM), and aspirin (IC (50) = 279.44 ± 4.40 µM). Compound 4 was also inactive in comparison with other tested Hypericum compounds.

Synthesis and antileishmanial and antimicrobial activities of some 2,3-disubstituted 3H-quinazolin-4-ones

A series of 2,3-disubstituted 3H-quinazolin-4-ones was synthesized. Antimicrobial activities of the synthesized compounds were investigated against Gram (+ve) and Gram (–ve) bacteria, including B. subtilis, S. aureus, S. flexneri, P. aeruginosa, and S. typhi, and six fungi, namely Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glabrata using the broth microdilution method. Compounds 9, 11, and 12 showed significant activities against the selected bacterial cultures, while 7–10, 12, 15, and 16 showed good to moderate antifungal activities. Compound 11 exhibited strongest leishmanicidal activity against Leishmania major (MHOM/PK/88/DESTO) promastigotes, while other compounds showed weak to moderate leishmanicidal activities.

Two new lignan glycosides from Trachelospermum lucidum (D. Don) Schum

Two new lignans (1 and 2) having a diarylhydroxybutyrolactone skeleton were isolated from the leaves of Trachelospermum lucidum (D. Don) Schum. Their structures were elucidated to be apocynotrachelolegnin 5′-O-β-d-glucopyranoside (1) and rafanotrachelogenin 4-O-β-d-glucopyranoside (2) on the basis of spectroscopic analysis. Two known lignans, matairesionoside-4-O-β-d-glucoside (3) and trachelosiaside (4), were also isolated from Trachelospermum lucidum.

A Xanthone Dixylopyranoside from Swertia thomsonii

A xanthone dixylopyranoside has been isolated from Swertia thomsonii C. B. Clarke and its structure established as 1,7-dihydroxy-3,8-dimethoxyxanthone 1-O-[β-D-xylopyranosyl- (1→4)D-xylopyranoside on the basis of spectral evidence, particularly 2D NMR studies. Three known compounds, 1,7-dihydroxy-3,8-dimethoxyxanthone, swertianin (1,7,8-trihydroxy- 3-methoxy-xanthone) and ursolic acid were also isolated from this species.

Diterpenoid alkaloids from Delphinium uncinatum

Abstract From the aerial parts of Delphinium uncinatum a new diterpenoid uncinatine and four known norditerpenoid alkaloids have been isolated. By spectral data ( 1 H and 13 C NMR) the known compounds were established as 14-acetylperegrine, 14-acetylvirescenine, condelphine and delbrusine. The structure of the new alkaloid was deduced by 1D and 2D NMR techniques.

Norditerpenoid alkaloids from Delphinium pyrimadale

Abstract From the aerial parts of Delphinium pyrimadale a new norditerpenoid alkaloid, 8-acetylcondelphine, has been isolated, together with the known alkaloids isotalatizidine, condelphine and senbusine C. The structure of the new alkaloid was established on the basis of 1H, 13C, APT, DEPT homonuclear COSY, HETCOR and COLOC NMR spectral studies and by chemical reactions.

Royleanumioside – a new phytotoxic triterpenoid from Teucrium royleanum

Royleanumioside (1), a new lupane type triterpenoid, was secluded from the CHCl3 soluble fraction of Teucrium royleanum. The structure of royleanumioside (1) was ascertained by spectral studies including 1D and 2D NMR spectroscopy and by the assessment with the reported data in literature. This new identified compound 1 was further tested for its phytotoxic activity against lettuce seedlings. Interestingly royleanumioside (1) had shown moderate phytotoxic activity.

One New Royleanumoate from Teucrium royleanum Wall. ex Benth

One new royleanumoate, a benzene ester (1), has been isolated from T. royleanum Wall. ex Benth along with two known compounds, namely, 3,4-dihydroxymethyl benzoate (2) and oleanolic acid (3). The structure elucidation of the isolated compounds was established on two-dimensional (2D) NMR techniques including heteronuclear multiple bond correlation (HMBC), heteronuclear multiple quantum Coherence (HMQC), and correlation spectroscopy (COSY) experiment.