Flavonoid glycosides and methylinositol fromEbenus haussknechtii

Revision of NMR assignment for Morin-3-O-glucoside and microbial production of Morin-2'-O-glucoside

Morin is a flavonol having 2',4'-dihydroxy group on B-ring identified especially in Moraceae plants. While morin is widely known, its glycosides are relatively rare. To the best of our knowledge, morin-3-O-glucoside (1) was first reported in 2008. However, the reported chemical shift values of 1 were unsatisfactory with those of the aglycone, morin, which is rather similar to quercetin-3-O-glucoside (2). Therefore, we prepared morin-3-O-glucoside (1) by microbial transformation of morin with Cunninghamella sp., and the NMR assignment was reinvestigated. The microbial culture also produced another compound (3). The NMR and MS analyses of 3 revealed it as a novel compound, morin-2'-O-glucoside (3).In this study, the revision of the NMR assignment of morin-3-O-glucoside (1), and the preparation and structural elucidation of a novel compound, morin-2'-O-glucoside (3), were described.

Glycosides from the leaves of Fraxinus Hubeiensis

Fraxinus hubeiensis is a plant endemic to China and widely used as folk medicine to treat various diseases. However, its chemical constituents have never been reported sufficiently. Thus, the primary objective of this study was to investigate the phytochemical constituents and biological activities of F. hubeiensis leaves. Hence, combined column chromatographic and spectroscopic techniques were used to identify and characterize the secondary metabolites such as a pair of 3-keto-glycoside epimers (1) and (2), along with five known compounds (3 ~ 7). The results of α-glucosidase inhibitory activity exhibited that 1 and 2 had moderate activity with IC50 values of 359.50 and 468.43 µM, respectively, compared to a positive control acarbose with the IC50 value of 164.08 µM. However, Compounds 1-6 were shown to be inactive against the tested microbes.

Morin Attenuated Cerebral Ischemia/Reperfusion Injury Through Promoting Angiogenesis Mediated by Angiopoietin-1-Tie-2 Axis and Wnt/β-Catenin Pathway

Cerebral damage following cerebral ischemia/reperfusion injury affects the neurological deficits and motor impairment of stroke patients in the long-term period. Angiogenesis, the essential process for restoration of cerebral blood flow (CBF) in the ischemic brain, promotes the recovery of neurological function following ischemia. The aim of this study was to investigate the long-term effects of morin on angiogenesis and functional outcomes in a middle cerebral artery occlusion (MCAO) and reperfusion model. Male Wistar rats were subjected to MCAO, and they were administered 30 mg/kg of morin at reperfusion via i.p. injection daily for 14 days. Fourteen days after I/R injury, the rats were evaluated for the brain damage, and angiogenic factors involved in Ang1/Tie-2 and Wnt/β-catenin signaling. In addition, at 1, 7, and 14 days after reperfusion, rotarod and pole tests were performed to investigate the functional recovery. We found morin significantly reduced the infarct size, blood-brain barrier (BBB) leakage, and apoptotic cells at 14 days after I/R injury. It also promoted angiogenesis via boosting the expression of angiogenic proteins, such as angiopoietin 1 (Ang1), Tie-2, Wnt3α, β-catenin, and cyclin D1. Morin-mediated angiogenesis was confirmed by a significant increase in microvessel's density in the penumbra area and an increase in von Willebrand factor (vWF) protein expression of the morin-treated rats. Moreover, the rotarod and pole tests also demonstrated morin increased functional recovery in the morin-treated rats compared to the vehicle rats. Therefore, our data exposed that morin promotes angiogenesis and improves functional outcomes in MCAO and reperfusion rats.

Morin protects the blood-brain barrier integrity against cerebral ischemia reperfusion through anti-inflammatory actions in rats

This study aimed to investigate the effects of morin on cerebral damage and blood–brain barrier (BBB) integrity in a middle cerebral artery occlusion (MCAO) and reperfusion model. Wistar rats were exposed to MCAO for 2 h, followed by reperfusion. Thirty mg/kg of morin was administered via intraperitoneal injection at the different time points: before ischemia, during ischemia, and at reperfusion. The rats were divided into five groups, including sham, vehicle, and three groups of morin. Twenty-four hours after reperfusion, the rats were tested for neurological deficits, and the brains were harvested to assess brain damage. In addition, brains were harvested 72 h to determine BBB disruption. We found that morin significantly reduced reactive oxygen species production and lipid peroxidation. It also decreased inflammation via reducing the expression of Toll-like receptor 4, nuclear factor kappa-beta. Morin ameliorated cerebral damage and reduced apoptosis through decreasing the cerebral infarct size, including apoptotic cell death. Moreover, morin decreased the BBB damage via reducing Evans blue extravasation, neutrophil infiltration, and increasing tight junction protein expression. Therefore, morin protected against cerebral and BBB damage by attenuating oxidative stress, inflammation, and apoptosis in MCAO and reperfusion models.

Antimicrobial steroidal saponin and oleanane-type triterpenoid saponins from Paullinia pinnata

BACKGROUND

Paullinia pinnata L. (Sapindaceae) is an African woody vine, which is widely used in traditional medicine for the treatment of human malaria, erectile dysfunction and bacterial infections. A phytochemical investigation of its methanol leaf and stem extracts led to the isolation of seven compounds which were evaluated for their antimicrobial properties.

METHODS

The extracts were fractionated and compounds were isolated by chromatographic methods. Their structures were elucidated from their spectroscopic data in conjunction with those reported in literature. The antimicrobial activities of the crude extracts, fractions and compounds were evaluated against bacteria, yeasts and dermatophytes using the broth micro-dilution technique.

RESULTS

Seven compounds: 2-O-methyl-L-chiro-inositol (1), β-sitosterol (2), friedelin (3), 3β-(β-D-Glucopyranosyloxy) stigmast-5-ene (4), (3β)-3-O-(2'-Acetamido-2'-deoxy-β-D-glucopyranosyl) oleanolic acid (5), (3β,16α-hydroxy)-3-O-(2'-Acetamido-2'-deoxy-β-D-glucopyranosyl) echinocystic acid (6) and (3β)-3-O-[β-D-glucopyranosyl-(1″-3')-2'-acetamido-2'-deoxy-β-D-galactopyranosyl]oleanolic acid (7) were isolated. Compounds 5 and 7 showed the best antibacterial and anti-yeast activities respectively (MIC value range of 0.78-6.25 and 1.56-6.25 μg/ml), while 6 exhibited the best anti-dermatophytic activity (MIC value range of 6.25-25 μg/ml).

CONCLUSION

The results of the present findings could be considered interesting, taking into account the global disease burden of these susceptible microorganisms, in conjunction with the search for alternative and complementary medicines.

Antityphoid and radical scavenging properties of the methanol extracts and compounds from the aerial part of Paullinia pinnata

Paullinia pinnata Linn (Sapindaceae) is a medicinal plant, locally used in the West Region of Cameroon for the treatment of typhoid fever. This work was designed to evaluate the antityphoid and antioxidant activities of the extracts and compounds of P. pinnata.

The methanol extracts of the leaves and stems were tested for antityphoid and antioxidant activities. Compounds were isolated, and their structures elucidated by analysis of spectroscopic data in conjuction with literature data and tested for the same activities. The leaf extract was also tested in vivo for its antityphoid potential in a Salmonella typhimurium-induced typhoid fever model in Wistar rats.

Seven known compounds: methylinositol (1), β-sitosterol (2), friedelin (3), 3β-(β-D-Glucopyranosyloxy)stigmast-5-ene (4), (3β)-3-O-(2′-Acetamido-2′-deoxy-β-D-glucopyranosyl) oleanolic acid (5), (3β,16α-hydroxy)-3-O-(2′-Acetamido-2′-deoxy-β-D-glucopyranosyl) echinocystic acid (6) and (3β,)-3-O-[β-D-glucopyranosyl-(1″-3′)-2′-acetamido-2′-deoxy-β-D-galactopyranosyl]oleanolic acid (7) were isolated. Compounds 5 and 1 showed the highest antibacterial (MIC = 0.781-1.562 μg/ml) and DPPH radical scavenging (RSa50 = 19.27 ± 4.43 μg/ml) activities respectively. The maximum extract dose (446.00 mg/kg bw) had comparable activity with ciprofloxacin (7.14 mg/kg bw) and oxytetracycline (5 mg/kg bw). The extract induced significant dose-dependent increase of WBCs and lymphocytes.

These results support the ethnomedicinal use of P. pinnata and its isolated Compounds could be useful in the standardization of antityphoid phytomedicine from it.

Phenolic glycosides with antimalarial activity from Grevillea "Poorinda Queen"

In search of new antimalarial compounds, three new phenolic glycosides, robustasides E (1), F (2), and G (3), in addition to the known compounds robustaside D (4) and quercetin-7-O-[α-l-rhamnopyranosyl(1→6)-β-d-galactopyranoside] (5), were identified during chemical investigations of the MeOH extract from the leaves and twigs of Grevillea "Poorinda Queen". The chemical structures of the new compounds were elucidated through 2D NMR spectroscopy, while the absolute configuration of the sugar was elucidated through chemical degradation and comparison with an authentic standard. Discussed in detail are the isolation and structure elucidation of 1-3, as well as the associated in vitro anitmalarial activities for 1-5. Also discussed are the in vivo anitmalarial and in vitro cytotoxic activities for 1, 3, and 4.