Maitreyee Banerjee

Search for a potent microbicidal spermicide from the isolates of Shorea robusta resin

BACKGROUND An alarming increase in global population is the root cause of poverty, malnutrition, sexually transmitted infections (STIs) and many other social problems. Microbicidal spermicides possessing dual function of contraception and STI protection can effectively combat this problem, and their development is of utmost importance at present. STUDY DESIGN A major metabolite isolated from Shorea robusta resin was spectroscopically characterized as asiatic acid. Spermicidal efficacy of the isolate was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) double fluoroprobe staining, (b) hypoosmotic swelling test and (c) scanning electron microscopy. Antimicrobial efficacy was assessed by disc diffusion and broth dilution methods using human isolates of bacteria (Escherichia coli ATCC 25938 and Pseudomonas aeruginosa 71) and fungus (Candida tropicalis). RESULTS The minimum effective concentration of asiatic acid that induced instantaneous immobilization of rat spermatozoa in vitro was 125 mcg/mL. The mechanism of action involved disruption of sperm plasma membrane. The microbicidal efficacy was found to be moderate for vaginal pathogens, with no effect on normal vaginal flora. CONCLUSION Asiatic acid possesses appreciable spermicidal and microbicidal potential and may be explored as an effective microbicidal spermicide.

I2 catalyzed Friedel–Crafts alkylation reaction of substituted anilines with ninhydrin: formation of novel products and their antimicrobial evaluation

Friedel–Crafts reaction of differently substituted anilines with ninhydrin in the presence of molecular iodine at ambient temperature constitutes a facile, cost effective, and regioselective synthesis of a series of 2-mono/2,2-bis-(amino-phenyl)-indane-1,3-dione derivatives. Under identical conditions, use of different substituents in aniline ring led to the formation of different products, emphasizing the pivotal role of the nature and position of the substituents in product formation. In vitro antimicrobial activity evaluation of the synthesized molecules against eight bacterial and four fungal strains revealed that four of them possess duel efficacies (bactericidal as well as fungicidal). The activities are attributed to the disruption of architecture of the microbes as revealed from ultrastructural studies (SEM).Graphical Abstract

Synthesis and Characterization of Furo[3,2-h]Quinoliniums as Potent Non- Detergent Spermicides

7-Aryl substituted furo[3,2-h]quinoliniums have been synthesised in two steps from 5-chloro-8-hydroxy-7- iodo-quinoline through a tandem Sonogashira alkynylation-cyclization pathway using aryl acetylenes followed by quaternisation reaction with alkyl halides under microwave irradiation. The compounds have been characterized spectroscopically and assessed for their sperm-immobilizing efficacy in vitro by modified Sander–Cramer test. Most of the derivatives showed potent spermicidal effect with minimum effective concentration (MEC) ranging from 125�g/ml – 1mg/ml. The results were further confirmed by double fluoroprobe staining with syber14/PI (Propidium Iodide). The mode of spermicidal action was assessed by (a) Hypo-osmotic swelling tests and (b) Scanning electron microscopy. The compounds have been found to be nontoxic to lactobacillus in 36 hours of culture whereas mild to moderately effective on common vaginal pathogens. Taken together it can be inferred that the water-soluble salts prepared from facile technique are potential candidates for spermicides and could further be utilized for the preparation of vaginal contraceptives.

Amberlite IRA 402(OH)-mediated synthesis and evaluation of fused tricyclic quinolinium salts as potent non-detergent type microbicidal spermicides

Fused tricyclic oxazaquinolinium salts were synthesized using Amberlite IRA 402(OH) in water and assessed for their sperm-immobilizing efficacy in vitro by modified Sander–Cramer test followed by double fluoroprobe staining of rat sperm. Out of 11 derivatives 3 showed potent spermicidal effect. The mode of spermicidal action was assessed by (a) Hypoosmotic swelling tests, (b) Lipid peroxidation studies, and (c) scanning electron microscopy. Antimicrobial efficacies of the potent derivatives, assessed by disc diffusion as well as by agar and broth dilution methods using human isolates of bacteria and fungi, revealed their moderate antimicrobial potential. The compounds, found to be nontoxic to rabbit erythrocytes by haemolytic assay, may be exploited as microbicidal spermicides.

Insights of Spermicidal Research: An Update

Spermicides came into existence as a method of contraception for over hundred years. Since then, investigations and developments in this field have led to more and more fruitful as well as promising results but still left enough scope for further studies. The titled article manifests a brief discussion on the development of spermicides from different natural and synthetic sources, a compilation of the promising molecules and even extracts and includes an outline of the basic physiology behind the bioactivity. Since spermicides are only one among several other methods of contraception adopted and practiced, an attempt has been made to probe the necessity and advantage of spermicides over other modes of contraception, emphasizing on the requirements and scope of future investigations in this field.

Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions

Summary A new series of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and pyrrolo[1,2-a]phenanthrolines were efficiently built up from an 8-hydroxyquinoline derivative or phenanthroline via 1,3-dipolar cycloaddition reaction involving non-stabilized azomethine ylides, generated in situ from the parent furo[3,2-h]quinoliniums/phenanthroliums, in presence of a copper(II) chloride–phenanthroline catalytic system. The methodology combines general applicability with high yields.