Croblongifolin, a new anticancer clerodane from Croton oblongifolius

A new furoclerodane, croblongifolin, together with one known clerodane, crovatin and one known labdane, nidorellol, were isolated from the stem bark of Croton oblongifolius. Structures were established based on spectroscopic and X-ray analysis. Croblongifolin showed a significant cytotoxicity against various human tumor cell lines including HEP-G2, SW620, CHAGO, KATO3 and BT474.     

Acemannan Stimulates Gingival Fibroblast Proliferation; Expressions of Keratinocyte Growth Factor-1, Vascular Endothelial Growth Factor,and Type I Collagen; and Wound Healing

Aloe vera has long been used as a traditional medicine for inducing wound healing. Gingival fibroblasts (GFs) play an important role in oral wound healing. In this study, we investigated the effects of acemannan, a polysaccharide extracted from Aloe vera gel, on GF proliferation; keratinocyte growth factor-1 (KGF-1), vascular endothelial growth factor (VEGF), and type I collagen production; and oral wound healing in rats. [³H]-Thymidine incorporation assay and ELISA were used. Punch biopsy wounds were created at the hard palate of male Sprague Dawley rats. All treatments (normal saline; 0.1% triamcinolone acetonide; plain 1% Carbopol^®; and Carbopol^® containing 0.5%, 1%, and 2% acemannan (w/w)) were applied daily. Wounded areas and histological features were observed at day 7 after treatment. From our studies, acemannan at concentrations of 2, 4, 8, and 16 mg/ml significantly induced cell proliferation (P<0.05). Acemannan concentrations between 2 – 16 mg/ml significantly stimulated KGF-1, VEGF, and type I collagen expressions (P<0.05). Wound healing of animals receiving Carbopol^® containing 0.5% acemannan (w/w) was significantly better than that of the other groups (P<0.05). These findings suggest that acemannan plays a significant role in the oral wound healing process via the induction of fibroblast proliferation and stimulation of KGF-1, VEGF, and type I collagen expressions.     

Alpha-glucosidase inhibitor proteins from Sesbania grandiflora flowers

Two alpha-glucosidase inhibitors were isolated from the flowers of Sesbania grandiflora and named SGF60 and SGF90. The procedure involved extraction with phosphate buffer, precipitation with ammonium sulfate, ion-exchange chromatography on DEAE-cellulose and gel filtration on Superdex-200. These proteins were identified by using tandem mass spectrometry. The results show partial amino acid sequences of SGF60 similar to p27SJ, a protein from Hypericum perforatum found to suppress HIV-1 gene expression. SGF90 matched a beta-glucosidase from Arabidopsis thaliana.     

Effect of acemannan,an extracted polysaccharide from Aloe vera,on BMSCs proliferation,differentiation, extracellular matrix synthesis,mineralization, and bone formation in a tooth extraction model

Aloe vera is a traditional wound healing medicine. We hypothesized acemannan, a polysaccharide extracted from Aloe vera gel, could affect bone formation. Primary rat bone marrow stromal cells (BMSCs) were treated with various concentrations of acemannan. New DNA synthesis, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein, osteopontin expression, and mineralization were determined by [³H] thymidine incorporation assay, ELISA, biochemical assay, western blotting, and Alizarin Red staining, respectively. In an animal study, mandibular right incisors of male Sprague–Dawley rats were extracted and an acemannan treated sponge was placed in the socket. After 1, 2, and 4 weeks, the mandibles were dissected. Bone formation was evaluated by dual-energy X-ray absorptiometry and histopathological examination. The in vitro results revealed acemannan significantly increased BMSC proliferation, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein and osteopontin expression, and mineralization. In-vivo results showed acemannan-treated groups had higher bone mineral density and faster bone healing compared with untreated controls. A substantial ingrowth of bone trabeculae was observed in acemannan-treated groups. These data suggest acemannan could function as a bioactive molecule inducing bone formation by stimulating BMSCs proliferation, differentiation into osteoblasts, and extracellular matrix synthesis. Acemannan could be a candidate natural biomaterial for bone regeneration.     

Evaluation of the safety and relative bioavailability of a new dihydroartemisinin tablet formulation in healthy Thai volunteers

A new dihydroartemisinin (DHA) tablet formulation has been developed by the Thai Government Pharmaceutical Organization (GPO). In this report, its in vitro dissolution and in vivo pharmacokinetics as well as its safety in healthy volunteers were evaluated, using the DHA tablet made by Dafra Pharma NV as a reference. A two-period crossover clinical study design was utilised. Twenty-four volunteers were randomly allocated to two sequences (12 volunteers in each) to receive a 200mg single oral dose of either the GPO or Dafra formulation with a wash-out period of 5-7 days. In vitro, the GPO formulation dissolved more readily. In vivo, the GPO formulation had a higher maximum plasma concentration and approximately 149% (90% CI 125-179%) greater bioavailability. Both formulations were well tolerated. Interestingly, significant decreases in haemoglobin and haematocrit values (P<0.001) were noted following administration of one dose of DHA (decrease of 0.73 g/dl haemoglobin and 2.0% haematocrit compared with baseline) or two doses of DHA (decrease of 0.95 g/dl haemoglobin and 3.3% haematocrit compared with baseline). The second dose was associated with additional toxicity compared with one dose with regard to haematocrit (P<0.001) but not haemoglobin. This finding warrants further investigation, since the drug will be used for the treatment of malaria in which anaemia is a consequence.     

Molecular cloning and sequence analysis of alboaggregin B

Green pit viper (Trimeresurus albolabris) venom contains a variety of C-type lectin-like proteins (CLPs) causing platelet aggregation and consumptive thrombocytopenia in biting victims. Alboaggregin B (AL-B), a heterodimeric glycoprotein (Gp) Ib-binding protein, was purified from the venom, but there is no reported cDNA sequence and the platelet agglutination mechanism is poorly understood. The full-length AL-B beta clone was obtained from T. albolabris venom gland cDNA library. AL-B alpha was, later, derived using 3'-RACE based on the conserved sequence. In this study, purified AL-B dimer agglutinated human platelets with the EC(50) of 180 nM and was completely inhibited by anti GpIb antibody. MALDI ToF mass spectroscopy found no glycosylation. The peptide mass fingerprints were matched with deduced amino acid sequences of cloned genes. AL-B alpha and beta contained 156 and 146 amino acid, respectively, including 23-residue signal peptides. AL-B beta showed the conserved hydrophilic patches, putative sites for GpIb binding. Furthermore, there was another conserved motif (SRTY) exclusively in platelet-agglutinating AL-B, TSV-GPIb-BP and Mamushigin. We propose that these three CLPs may function as bivalent adhesive proteins linking two GpIb molecules on adjacent platelets.     

Clinical,radiographic, and histologic analysis of the effects of acemannan used in direct pulp capping of human primary teeth: short-term outcomes

Acemannan has been previously reported as a direct pulp-capping agent in animal study. This natural material demonstrated its biocompatibility and enhanced reparative dentin formation. The objective of this study was to investigate the action of acemannan as a direct pulp-capping material in human primary teeth with deep caries. Forty-two deeply carious mandibular primary molars from 37 children, aged 7–11 years old diagnosed with reversible pulpitis were studied. After completely removing the infected dentine, teeth with a pinpoint pulpal exposure were randomly divided into two treatment groups: acemannan or calcium hydroxide. A glass-ionomer cement base was applied to all teeth prior to restoration with stainless steel crowns. Clinical and radiographic evaluation was performed 6 months post-treatment. The teeth due to exfoliate were extracted and histopathologically evaluated for inflammation, dentine bridge formation, and soft tissue organization. At 6 months, the overall clinical and radiographic success rates of direct pulp capping with acemannan and calcium hydroxide at 6 months were 72.73 and 70.0 %, respectively. The histopathological results indicated that the acemannan-treated group had significantly better histopathological responses compared with the calcium hydroxide-treated group (p < 0.05). These data suggest acemannan offers a valuable alternative biomaterial for vital pulp therapy in primary teeth.     

Slow acting protein extract from fruit pulp of Momordica charantia with insulin secretagogue and insulinomimetic activities

The protein from Thai bitter gourd (Momordica charantia) fruit pulp was extracted and studied for its hypoglycemic effect. Subcutaneous administration of the protein extract (5, 10 mg/kg) significantly and markedly decreased plasma glucose concentrations in both normal and streptozotocin-induced diabetic rats in a dose-dependent manner. The onset of the protein extract-induced antihyperglycemia/hypoglycemia was observed at 4 and 6 h in diabetic and normal rats, respectively. This protein extract also raised plasma insulin concentrations by 2 fold 4 h following subcutaneous administration. In perfused rat pancreas, the protein extract (10 mug/ml) increased insulin secretion, but not glucagon secretion. The increase in insulin secretion was apparent within 5 min of administration and was persistent during 30 min of administration. Furthermore, the protein extract enhanced glucose uptake into C(2)C(12) myocytes and 3T3-L1 adipocytes. Time course experiments performed in rat adipocytes revealed that M. charantia protein extract significantly increased glucose uptake after 4 and 6 h of incubation. Thus, the M. charantia protein extract, a slow acting chemical, exerted both insulin secretagogue and insulinomimetic activities to lower blood glucose concentrations in vivo.     

New halimane diterpenoids from Croton oblongifolius

Three new halimane-type diterpenoids, crotohalimaneic acid ( 1), crotohalimoneic acid ( 2) and 12-benzoyloxycrotohalimaneic acid ( 3), were isolated from the stem bark of Croton oblongifolius Roxb. Their structures were established on the basis of spectroscopic and X-ray analysis. Compounds 1 and 2 showed non-specific strong cytotoxicity against a panel of human tumor cell lines; whereas 3 was inactive.