Psiguanol, a novel α-pyrone derivative from Psidium guajava leaves and vasorelaxant activity in rat aorta cells through intracellular cGMP-dependent opening of calcium-activated potassium channels.

The phytochemical investigation of Psidium guajava leaves led to the isolation of total nineteen compounds which belongs to meroterpenoids, flavonoid, phenolics, and triterpenoids. The compounds were isolated using extensive chromatography techniques and identified as psiguanol (4), as new compound along with guajadial (1), psidial A (2), ß-caryophyllene (3), quercetin (5), avicularin (6), guaijaverin (7), hyperin (8), rutin (9), ursolic acid (10), corosolic acid (11), asiatic acid (12), ß-sitosterol (13), ß-sitosterol-D-glucoside (14), ellagic acid (15), 3,3',4'-trimethylellagic acid 4-O-glucoside (16), protocatechuic acid (17), gallic acid (18), and tricosanoic acid (19) as known molecules. The compound 16 was isolated for the first time from this plant. The isolated compounds were evaluated for vasorelaxation activity in rat aorta cells and it was observed that compound 4 exhibited the most potent vasorelaxation response in the ex-vivo model in isolated rat aorta cells. Mechanistically, the vasorelaxation activity of 4 was mediated through cGMP-dependent BKCa channel opening.

Enhancement of survival of alginate-encapsulated Lactobacillus casei NCDC 298.

BACKGROUND: Micro-encapsulation of hydrocolloids improves the survival of sensitive probiotic bacteria in the harsh conditions that prevail in foods and during gastrointestinal passage by segregating them from environments. Incorporation of additives in encapsulating hydrocolloids and coatings of microcapsules further improves the survival of the probiotics. In this study, the effect of incorporation of resistant-maize starch in alginate for micro-encapsulation and coating of microcapsules with poly-l-lysine, stearic acid and bees wax on the survival of encapsulated Lactobacillus casei NCDC 298 at pH 1.5, 2% high bile salt, 65 °C for 20 min and release of viable lactobacilli cells from the capsule matrix in simulated aqueous solutions of colonic pH were assessed. RESULTS: Addition of resistant maize starch (2%) improved the survival of encapsulated L. casei NCDC 298. Coating of microcapsules with poly-L-lysine did not further improve the protection of encapsulated cells from the harsh conditions; however, bees wax and stearic acid (2%) improved the survival under similar conditions. Incorporation of maize starch (2%) in alginate followed by coating of beads with stearic acid (2%) led to better protection and complete release of entrapped lactobacilli in simulated colonic pH solution was observed. CONCLUSION: Additional treatments improve the survival of alginate-encapsulated lactobacilli cells without hindering the release of active cells from the capsule matrix and hence, the resulting encapsulated probiotics can be exploited in the development of probiotic functional foods with better survival of sensitive probiotic organisms.

Skin uptake and clearance of ciclopirox following topical application.

The assessment of skin uptake and clearance are important to determine the efficiency and systemic safety of dermatological formulations. The objective of this study was to assess the skin uptake, clearance and possible systemic delivery of ciclopirox following topical application in Wistar rats. In vitro studies (3 h) were carried out in excised pig skin to assess the permeation and retention capacity of ciclopirox in skin layers using gel formulations (1% and 2% w/v). In vivo dermatopharmacokinetics (DPK) parameters were determined by measuring the drug levels in the skin as a function of time post application (0.5, 1, 1.5 and 2 h) and post removal (3, 4, 6 and 8 h) of the formulation in Wistar rats. The plasma drug concentrations were also determined in the same animals. In vitro data indicate the low permeability and high retention of ciclopirox in the stratum corneum. The DPK data observed indicate a higher Cmax value (175.43 ± 25.62 µg/cm2) and AUC (632.14 ± 102.26 µg.h/cm2) with the 2% (w/v) gel formulation. Further, the skin elimination of ciclopirox follows first order kinetics with a short half-life (t1/2 ~2 h). The fraction of drug reaching the systemic circulation was found to be significantly low (~0.15% of the applied dose). A relation between the drug concentration in the skin layers and the plasma was observed with a short lag period. The topical availability of ciclopirox was found to be relatively low and endured rapid clearance with minimal systemic uptake.

Comparative assessment of marginal accuracy of grade II titanium and Ni-Cr alloy before and after ceramic firing: An in vitro study.

OBJECTIVE: The aims of the study are to assess the marginal accuracy of base metal and titanium alloy casting and to evaluate the effect of repeated ceramic firing on the marginal accuracy of base metal and titanium alloy castings. MATERIALS AND METHODS: Twenty metal copings were fabricated with each casting material. Specimens were divided into 4 groups of 10 each representing base metal alloys castings without (Group A) and with metal shoulder margin (Group B), titanium castings without (Group C) and with metal shoulder margin (Group D). The measurement of fit of the metal copings was carried out before the ceramic firing at four different points and the same was followed after porcelain build-up. RESULTS: Significant difference was found when Ni-Cr alloy samples were compared with Grade II titanium samples both before and after ceramic firings. The titanium castings with metal shoulder margin showed highest microgap among all the materials tested. CONCLUSIONS: Based on the results that were found and within the limitations of the study design, it can be concluded that there is marginal discrepancy in the copings made from Ni-Cr and Grade II titanium. This marginal discrepancy increased after ceramic firing cycles for both Ni-Cr and Grade II titanium. The comparative statistical analysis for copings with metal-collar showed maximum discrepancy for Group D. The comparative statistical analysis for copings without metal-collar showed maximum discrepancy for Group C.

A comprehensive study to evaluate the effect of constant low voltage iontophoresis on transungual delivery.

Treatment of nail diseases by topical drug delivery continues to draw much attention in the recent days. This study aims to systematically investigate the effect of constant voltage iontophoresis in the transungual drug delivery, using ciclopirox as a model drug. Preliminary permeation studies were carried out by applying constant voltage (6 V for 24 h) using a gel formulation across the human nail plate in a Franz diffusion cell. Different protocols have been studied to authenticate the potential of the proposed technique. Antifungal studies were carried out to assess the pharmacodynamic effect of drug depot formed in the nail plate. Initial studies revealed that application of constant voltage iontophoresis enhanced the permeation by an order of magnitude (p = 0.019) and delivered significant amount of drug into the deeper nail layers. Noticeably higher permeation was observed during the active phase in on-off studies. Excellent correlation was observed in permeation (r(2) = 0.98) and drug load (r(2) = 0.97) with the increase in applied voltage (3-12 V), indicating that the current technique is predictable. The data observed suggest that any further increase in voltage could eventually lead to increase in the permeation and drug load, as the saturation level is very distant. Furthermore, the enhancement in permeation with the applied voltage (3-12 V) was found to be 6-20 folds, compared to the passive process. Results of step up and step down studies substantiated the viability of the current technique. Zone of inhibition measured during the antifungal studies demonstrated that the drug molecules loaded into the nail plate by low voltage iontophoresis is active and releases over an extended period of time (~32 days). Given the excellent results, the current technique could be used as an effective approach for the delivery of antimycotics, which would localize the drug at the infection site and potentially offer higher patient compliance.

Effect of different impression techniques on the dimensional accuracy of impressions using various elastomeric impression materials: an in vitro study.

UNLABELLED: Production of exemplary crowns and fixed partial dentures depends upon the usage of impression material and its technique of usage that accurately reproduces prepared teeth and their relationship to the adjacent oral structure. AIM: To evaluate the linear dimensional accuracy of the elastomeric impressions using various impression techniques using different combinations of viscosities of impression materials. MATERIALS AND METHODS: Crown preparation was done in a dentulous acrylic resin denture base model with six natural teeth embedded into it was made to represent the dentulous maxillary arch. A total of 55 impressions were obtained and poured in die stone using various impression techniques with different combinations of viscosities of impression materials. RESULTS: Among the six techniques used, the heavy body light body two-step technique using custom tray showed the least distortion which was closely followed by the putty wash two-step technique with 2 mm spacer using stock tray. CONCLUSION: The study revealed that the heavy body light body two-step technique with custom tray provided the best results. CLINICAL SIGNIFICANCE: Dimensional accuracy of impressions is very much required for precisely fitting of prosthesis. This study may be helpful to select the technique and materials as per clinical requirement of accuracy of impressions.

Novel Approaches in Formulation and Drug Delivery using Contact Lenses.

The success of ocular delivery relies on the potential to enhance the drug bioavailability by controlled and extended release of drug on the eye surface. Several new approaches have been attempted to augment the competence and diminish the intrinsic side effects of existing ocular drug delivery systems. In this contest, progress has been made to develop drug-eluting contact lens using different techniques, which have the potential to control and sustain the delivery of drug. Further, the availability of novel polymers have facilitated and promoted the utility of contact lenses in ocular drug delivery. Several research groups have already explored the feasibility and potential of contact lens using conventional drugs for the treatment of periocular and intraocular diseases. Contact lenses formulated using modern technology exhibits high loading, controlled drug release, apposite thickness, water content, superior mechanical and optical properties as compared to commercial lenses. In general, this review discus various factors and approaches designed and explored for the successful delivery of ophthalmic drugs using contact lenses as drug delivery device.

Conjugated linoleic acid producing potential of lactobacilli isolated from the rumen of cattle.

Lactobacilli isolated from the rumen of cattle were subjected to morphological and biochemical characterizations followed by PCR-based identification. Among isolates, Lactobacillus brevis was found to be the most prevalent species in the rumen. For in vitro conjugated linoleic acid (CLA) production, the two isolates of L. brevis and one each of Lactobacillus viridescens and Lactobacillus lactis were selected. The sunflower oil (i.e., 0.25, 0.5 and 1.0%; a rich source of linoleic acid) was added to skim milk as a substrate for CLA production by isolates at 37 degrees C/12 h. L. brevis 02 was found to be the most potential CLA producer (10.53 mg CLA/g fat) at 0.25% concentration of sunflower oil followed by L. brevis 01 (8.27 mg CLA/g fat). However, at higher level of sunflower oil (i.e., 1.0%), L. lactis was the highest CLA producer (9.22 mg/g fat) when compared to L. brevis and L. viridescens. The results indicated that L. brevis and/or CLA production was inhibited with increasing concentration of sunflower oil in skim milk. In contrast, L. lactis and L. viridescens could tolerate the increasing concentrations of sunflower oil and produced higher CLA. Overall, L. brevis extends a possibility to be used as a direct-fed microbial for ruminants to increase the CLA content in milk, however, in vivo trials are needed for validation of results obtained.

Effect of administration of anaerobic fungi isolated from cattle and wild blue bull (Boselaphus tragocamelus) on growth rate and fibre utilization in buffalo calves.

Fifteen Murrah buffalo calves (age about 10 months, 163-176 kg BW) were divided into three groups. Group I (Control) was fed a complete feed mixture consisted of 50% wheat straw and 50% concentrate mixture (contained per kg: maize 330 g, groundnut cake 210 g, mustard cake 120 g, wheat bran 200 g, de-oiled rice bran 110 g, mineral mixture 20 g and common salt 10 g) along with 2 kg green oats per animal and day to meet the vitamin A requirements. Calves of Groups II and III were fed with the Control diet supplemented with Orpinomyces sp. C-14 and Piromyces sp. WNG-12 cultures, respectively. The digestibility of DM was significantly highest with Piromyces sp. WNG-12 in Group III (62.2%) followed by Orpinomyces sp. C-14 in Group II (60.3%), and Control (53.5%). A similar pattern of increase in digestibility of crude protein and cell-wall contents was observed in treatment groups. The digestible energy in terms of percent total digestible nutrients was also significantly enhanced in Groups II (56.6%) and III (59.9%) when compared to Control (49.2%). The rumen fermentation parameters such as pH and NH3-N were found to be lower, whereas total nitrogen, tricarboxylic acid precipitable-, nitrogen, total volatile fatty acids and zoospore counts per millilitre of rumen liquor were significantly higher in fungal administered groups. After administration of fungal cultures, improvements of animal growth rate (i.e. body weight gain) and feed efficiency were also observed.

Hydrolytic activities of anaerobic fungi from wild blue bull (Boselaphus tragocamelus).

The anaerobic fungi play an active role in the plant fibre degradation by producing a wide array of potential hydrolytic enzymes in the rumen. In present study, 12 anaerobic fungal strains were isolated from the faecal samples of wild blue bull, and identified as species of Piromyces, Anaeromyces, Orpinomyces and Neocallimastix based on their morphological characteristics. Isolate WNG-12 (Piromyces sp.), showed maximum filter paper cellulase (23 mIU ml(-1)) and xylanase (127 mIU ml(-1)) activity, while WNG-5 (Piromyces sp.) showed maximum carboxymethyl cellulase activity (231 mIU ml(-1)). Based on the results obtained, it can be stated that Piromyces sp. WNG-12 may be a promising isolate in utilizing fibre rich diets in the rumen as evidenced by the production of hydrolytic enzymes in vitro.

In vitro degradation of wheat straw by anaerobic fungi from small ruminants.

Anaerobic ruminal fungi may play an active role in fibre degradation as evidenced by the production of different fibrolytic enzymes in culture filtrate. In the present study, 16 anaerobic fungal strains were isolated from ruminal and faecal samples of sheep and goats. Based on their morphological characteristics they were identified as species of Anaeromyces, Orpinomyces, Piromyces and Neocallimastix. Isolated Neocallimastix sp. from goat rumen showed a maximum activity of CMCase (47.9 mIU ml(-1)) and filter paper cellulase (48.3 mIU ml(-1)), while Anaeromyces sp. from sheep rumen showed a maximum xylanolytic activity (48.3 mIU ml(-1)). The cellobiase activity for all the isolates ranged from 178.0-182.7 mIU ml(-1). Based on the enzymatic activities, isolated Anaeromyces sp. from sheep rumen and Neocallimastix sp. from goat rumen were selected for their potential of in vitro fibre degradation. The highest in vitro digestibility of NDF (23.2%) and DM (34.4%) was shown for Neocallimastix sp. from goat rumen, as compared to the digestibility of NDF and DM in the control group of 17.5 and 25.0%, respectively.

Interaction of gut microflora with tannins in feeds.

Tannins (hydrolyzable and condensed) are water-soluble polyphenolic compounds that exert antinutritional effects on ruminants by forming complexes with dietary proteins. They limit nitrogen supply to animals, besides inhibiting the growth and activity of ruminal microflora. However, some gastrointestinal microbes are able to break tannin-protein complexes while preferentially degrading hydrolyzable tannins (HTs). Streptococcus gallolyticus, Lonepinella koalarum and Selenomonas ruminantium are the dominant bacterial species that have the ability to degrade HTs. These tanninolytic microorganisms possess tannin-degrading ability and have developed certain mechanisms to tolerate tannins in feeds. Hence, selection of efficient tanninolytic microbes and transinoculation among animals for long-term benefits become areas of intensive interest. Here, we review the effects of tannins on ruminants, the existence and significance of tannin-degrading microorganisms in diverse groups of animals and the mechanisms that tannin-degrading microorganisms have developed to counter the toxic effects of tannin.

Tannic acid resistance in ruminal streptococcal isolates.

Tannin degrading isolates of Streptococcus spp. from rumen of non-adaptive cattle, when grown in BHI broth, were able to tolerate tannic acid upto a level of 50 g/l. An increase in lag period from 1.5 to 6 h was observed for the isolates in presence of increased concentration of tannic acid. In addition, the morphology of gram positive diplococci converted to an elongated chain of 40-50 cells with increasing tannic acid from 1 to 4%. Qualitatively, the tannase activity was found to be present in the isolates tested, indicating their potential of being a tannin degrader.

In vitro degradation of cell-wall and digestibility of cereal straws treated with anaerobic ruminal fungi.

Ruminal fungal isolates (Orpinomyces sp.; C-14, Piromyces sp.; C-15, Orpinomyces sp.; B-13 and Anaeromyces sp.; B-6), were evaluated under anoxic conditions for their effect on in vitro dry matter digestibility, neutral detergent fibre, acid detergent fibre and acid detergent lignin using rice and wheat straw as substrate. There was no significant effect of the fungal isolates on the disappearance of the substrates along with rumen liquor when compared to control. The doses of 10(6) cfu/ml of the isolate were found to have maximum degradation of straws in comparison to the doses of 10(3) cfu/ml.