Manmeet Kumar

Mycotic keratitis: an overview of diagnosis and therapy

The increased incidence of fungal infections in the recent past has been attributed to the increase in the number of human immunodeficiency virus‐positive and AIDS patients. Early diagnosis of mycoses in patients is crucial for prompt antifungal therapy. The yield of clinical examination in the diagnosis of keratomycosis is 63–83% and KOH mount is 91%. This still highlights the limitation of routine clinical examination and smear examination, which is not performing 100% efficiently. It is for these 37%, 17% and 9% of cases, every day advanced technologies are called for. Those who deal with patient care are aware of certainties and uncertainties of results of clinical examination. The best reported figures at specialized centres might not translate into clinical practice. Another factor to be kept in mind is that many patients who come after secondary and tertiary referrals are already treated with antibiotics, antivirals, steroids and sometimes even antifungals that distort the clinical picture completely. Further, one has to consider as well the cases caused by yeast‐like fungi, which resemble bacterial keratitis. Confirmation of diagnosis, not only in case of mycotic keratitis but also for other diseases, to initiate prompt and accurate therapy would avoid unnecessary and indiscriminate use of steroids/antibacterials/antivirals and antifungals.

Differential effects of formononetin and cladrin on osteoblast function, peak bone mass achievement and bioavailability in rats

Dietary soy isoflavones including genistein and daidzein have been shown to have favorable effects during estrogen deficiency in experimental animals and humans. We have evaluated osteogenic effect of cladrin and formononetin, two structurally related methoxydaidzeins found in soy food and other natural sources. Cladrin, at as low as 10 nM, maximally stimulated both osteoblast proliferation and differentiation by activating MEK-Erk pathway. On the other hand, formononetin maximally stimulated osteoblast differentiation at 100 nM that involved p38 MAPK pathway but had no effect on osteoblast proliferation. Unlike daidzein, these two compounds neither activated estrogen receptor in osteoblast nor had any effect on osteoclast differentiation. Daily oral administration of each of these compounds at 10.0 mg kg(-1) day(-1) dose to recently weaned female Sprague-Dawley rats for 30 consecutive days, increased bone mineral density at various anatomic positions studied. By dynamic histomorphometry of bone, we observed that rats treated with cladrin exhibited increased mineral apposition and bone formation rates compared with control, while formononetin had no effect. Cladrin had much better plasma bioavailability compared with formononetin. None of these compounds exhibited estrogen agonistic effect in uteri. Our data suggest that cladrin is more potent among the two in promoting parameters of peak bone mass achievement, which could be attributed to its stimulatory effect on osteoblast proliferation and better bioavailability. To the best of our knowledge, this is the first attempt to elucidate structure-activity relationship between the methoxylated forms of daidzein and their osteogenic effects.

Total extract and standardized fraction from the stem bark of Butea monosperma have osteoprotective action: evidence for the nonestrogenic osteogenic effect of the standardized fraction.

Objective: The aim of this study was to determine the skeletal effects of Butea total extract (BTE) and its acetone soluble fraction (ASF) from Butea monosperma, which is rich in methoxyisoflavones, in ovariectomized (OVx) rats, a model for postmenopausal bone loss. Methods: BTE (1.0 g kg−1 d−1) and ASF (100 mg kg−1 d−1) were given orally for 12 weeks to adult OVx rats. The sham-operated and ovariectomy + vehicle groups served as controls. Bone mineral density, osteoid formation (mineral apposition rate and bone formation rate), bone microarchitecture, and bone turnover/resorption markers were studied. Phytoestrogens in rats given BTE and ASF were analyzed by high-performance liquid chromatography. One-way analysis of variance was used to test significance of effects. Results: OVx rats treated with either BTE or ASF exhibited increased bone mineral density in trabecular bones and improved trabecular microarchitecture compared with the ovariectomy + vehicle group. ASF treatment was more efficient than BTE treatment in maintaining trabecular microarchitecture. Serum osteocalcin and urinary type 1 collagen levels in OVx rats treated with either BTE or ASF were significantly lower than those of the ovariectomy + vehicle group. ASF treatment led to increased mineral apposition rate and bone formation rate compared with ovariectomy + vehicle, whereas BTE had no such effect. In the uterotropic assay, BTE was mildly estrogenic in adult OVx rats. In immature rats, BTE exhibited both estrogenicity and antiestrogenicity. ASF had neither uterine estrogenicity nor antiestrogenicity. Analysis of phytoestrogens revealed significant enrichment of cladrin, isoformononetin, and medicarpin in ASF over BTE. Conclusions: Derived from B monosperma, ASF at a 10-fold lower dose than that of BTE was effective in preventing OVx-induced bone loss and stimulated new-bone formation.

Anti-osteoporotic constituents from Indian medicinal plants

The objective of this study was to determine the in vitro osteogenic activities of selected medicinal plants used traditionally in India. The compounds isolated from three plants viz. Allophylus serratus, Cissus quadrangularis and Vitex negundo were evaluated for their in vitro osteogenic activities. Primary cultures of osteoblasts were used to determine the effects of these components on osteoblast functions. Five of the fourteen compounds isolated led to increase in osteoblast differentiation and mineralization. These findings lend support to the use of Allophylus serratus, Cissus quadrangularis and Vitex negundo in traditional medicine.

A novel flavonoid isolated from the steam-bark of Ulmus wallichiana planchon stimulates osteoblast function and inhibits osteoclast and adipocyte differentiation.

(2S,3S)-Aromadendrin-6-C-β-d-glucopyranoside (AG) is a novel flavonol isolated from the extract of Ulmus wallichiana (Himalayan Elm). Extract of U. wallichiana is used as a traditional medicine for rapid fracture repair in India. We characterized the mechanism of action of AG in mouse bone cells by investigating its effect on the precursors of osteoblasts, osteoclasts and adipocytes. At nanomolar concentrations, AG increased differentiation of preosteoblasts obtained from neonatal mouse calvaria. The gene expression of osteogenic markers, including runt-related transcription factor 2 (Runx-2), bone morphogenetic protein-2 (BMP-2), type I collagen and osteocalcin were elevated in the preosteoblasts. The extracellular matrix mineralization was higher in preosteoblast and bone marrow cells when AG was present in the medium. Furthermore, AG protected the differentiated osteoblasts from serum deprivation-induced apoptosis, and increased the expression of the anti-osteoclastogenic cytokine, osteoprotegerin. It inhibited osteoclast differentiation of bone marrow precursor cells to osteoclasts in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and monocyte/macrophage-colony stimulating factor (M-CSF). Additionally, in 3T3-L1 preadipocytes, AG decreased the expression of genes involved in adipogenesis, including peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element binding protein (SREBP) and CCAAT/enhancer-binding protein alpha (CEBP/α), and induced apoptosis of differentiated adipocytes. Induction of adipogenic differentiation was also inhibited in the presence of AG. AG exhibited no estrogenic/antiestrogenic effect. Together, our data show that AG has potent osteogenic, anti-osteoclastogenic and anti-adipogenic effects, which may translate to a better skeletal outcome in postmenopausal osteoporosis.

Extract and fraction from Ulmus wallichiana Planchon promote peak bone achievement and have a nonestrogenic osteoprotective effect.

Objective: This study aimed to determine the skeletal effects of total ethanolic extract (TEE) and its butanolic fraction (BF) from the stem-bark of Ulmus wallichiana, which is rich in C-glycosylated flavonoids, in growing rats (for peak bone [PB] achievement) and in ovariectomized (OVx) rats (for menopausal bone loss). Methods: TEE (750 mg kg−1 d−1) and BF (50 mg kg−1 d−1) were given orally for 10 weeks to weaning female Sprague-Dawley rats and for 12 weeks to adult OVx rats of the same strain, respectively. In studies with OVx rats, sham operated + vehicle, OVx + 17&bgr;-estradiol, and OVx + vehicle groups served as various controls. Bone mineral density (BMD), biomechanical strength, bone histology, formations of osteoprogenitor cells, osteoid formation, and bone turnover/resorption markers were studied. Bioactive marker compounds in TEE and BF were analyzed by high-performance liquid chromatography. One-way analysis of variance was used to test significance of effects. Results: In growing rats, both TEE and BF increased BMD, bone strength, and bone formation rate, suggesting higher PB achievement. OVx rats treated with either TEE or BF exhibited increased BMD at various anatomical positions and improved bone strength and trabecular architecture compared with the OVx + vehicle group. Serum osteocalcin and urinary type 1 collagen degradation product levels in OVx rats treated with either TEE or BF were significantly lower than those of the OVx + vehicle group. Neither TEE nor BF exhibited uterine estrogenicity. Analysis of marker compounds revealed significant enrichment of two bioactive markers in BF over TEE. Conclusions: Derived from U wallichiana, BF at much a lower dose than TEE was effective in PB achievement and prevention of OVx-induced bone loss.

Constituents from fruits of Cupressus sempervirens.

Two new phenolic glycosides (1, 2), along with fourteen known compounds (3-16) have been isolated from the fruit of Cupressus sempervirens. The structures of these compounds were determined by spectroscopic analysis and were evaluated for their inhibitory activity against glycogen phosphorylase and glucose-6-phosphatase enzymes. Compounds 14 showed a moderate inhibition against glucose-6-phosphatase and 15 against glycogen phosphorylase enzymes.

Synthesis and antihyperglycemic activity of phenolic C-glycosides.

Various phenolic C-glycosides were evaluated for their in vitro and in vivo antihyperglycemic activity employing glucose uptake by rat muscle cell lines (L-6) and low dosed-streptozotocin-induced diabetic rats, respectively. Some of phenolic C-glycosides were isolated from Pterocarpus marsupium and Ulmus wallichiana and other were synthesized by unprotected sugar and phloroacetophenone using Sc(OTf)(3) in aqueous ethanol. Eight among tested compounds showed significant lowering of blood glucose level on low dosed-streptozotocin-induced diabetic rats. The compound 24 lowered the blood glucose levels by 34.9% and 33.6% during 0-5h and 0-24h, respectively, at the dose of 25mg/kg body weight which is comparable to standard antidiabetic drug metformin.

Quercetin-6-C-β-D-glucopyranoside isolated from Ulmus wallichiana planchon is more potent than quercetin in inhibiting osteoclastogenesis and mitigating ovariectomy-induced bone loss in rats.

Objective: The aim of this study was to determine the skeletal effect of quercetin-6-C-&bgr;-d-glucopyranoside (QCG) isolated from the extract of Ulmus wallichiana and compare this effect with quercetin (Q) in a rat model of postmenopausal bone loss. Methods: Murine bone marrow cells were used to study the effect of QCG or Q on osteoclast differentiation. QCG or Q (1.0 and 5.0 mg kg−1 d−1 doses) was administered orally to ovarietomized (OVx) rats for 12 weeks. Sham-operated + vehicle and OVx + vehicle groups served as positive and negative controls, respectively. Bone mineral density, bone microarchitecture, biomechanical strength, bone turnover markers, and uterotrophic effect were studied. One-way analysis of variance was used to test significance of effects. Results: QCG at 1.0 nM significantly inhibited differentiation of multinucleated osteoclasts and expression of osteoclastogenic genes from bone marrow cells, whereas Q at 10.0 &mgr;M had comparable results. OVx rats treated with QCG exhibited significantly higher bone mass and better microarchitecture in trabecular and cortical bones compared with OVx + vehicle. QCG treatment of OVx rats had better functional impact than did Q-treated OVx rats, evident from increased bone biomechanical strength. Serum osteocalcin and urinary fragments of type 1 collagen were significantly lower in QCG-treated OVx rats compared with OVx + vehicle group. The protective effect of QCG under ovariectomy-induced bone loss setting was found to be significantly better than Q. Uterine histomorphometry parameters of OVx rats did not change with QCG treatment. Conclusions: QCG improves bone biomechanical quality more effectively than Q through positive modifications of bone mineral density and bone microarchitecture without a hyperplastic effect on the uterus.

A novel flavonoid, 6-C-beta-d-glucopyranosyl-(2S,3S)-(+)-3',4',5,7-tetrahydroxyflavanone, isolated from Ulmus wallichiana Planchon mitigates ovariectomy-induced osteoporosis in rats.

Objective: The aim of this study was to determine the skeletal effect of 6-C-&bgr;-d-glucopyranosyl-(2S,3S)-(+)-3&vprime;,4&vprime;,5,7-tetrahydroxyflavanone (GTDF)/Ulmoside A, a new compound isolated from the extract of Ulmus wallichiana in a rat model of postmenopausal bone loss. Methods: GTDF (1.0 and 5.0 mg kg−1 d−1) was given orally to ovariectomized (OVx) rats (180-200 g) for 12 weeks. Sham operated + vehicle, ovariectomy + 17&bgr;-estradiol (2.5 &mgr;g kg−1 d−1), and ovariectomy + vehicle groups served as various controls. Bone mineral density (BMD), trabecular microarchitecture, bone biomechanical strength, levels of bone turnover/resorption markers, uterotropic effect, and plasma pharmacokinetics were studied. One-way analysis of variance was used to test significance of effects. Results: OVx rats treated with both doses of GTDF exhibited significantly higher BMD in the trabecular (distal femur, proximal tibia, and vertebrae) and cortical (femur shaft) regions compared with the ovariectomy + vehicle group. Micro-CT demonstrated that OVx rats treated with 5.0 mg kg−1 day−1 of GTDF had better bone microarchitectural parameters compared with the ovariectomy + vehicle group. Serum osteocalcin and urinary C-terminal teleopeptide of Type I collagen levels in OVx rats treated with GTDF (at both doses) were significantly lower than those in the ovariectomy + vehicle group. At neither of the two doses did GTDF exhibit uterine estrogenicity. A pharmacokinetic study revealed that GTDF achieved maximum plasma concentration (40.67 ng mL−1) at ∼1 hour, indicating its slow absorption. Its absolute bioavailability was found to be 1.04% with a plasma elimination half-life of ∼5 hours. Conclusions: GTDF, a novel compound isolated from U wallichiana extract, improves bone biomechanical quality through positive modifications of BMD and trabecular microarchitecture without a hyperplastic effect on the uterus.