Turbo-extraction of glycosides from Stevia rebaudiana using a fractional factorial design

ABSTRACT Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, leaf extract has recently called the attention of food industry as a proposal for natural sweetener. The sweet flavor is attributed to the glycosides, in especial stevioside and rebaudioside A, which are the plant main chemical markers. The aim of the work reported here was to optimize the turbo-extraction of stevia leaves using water, ethanol 70% and 90% (w/w) as green solvents. A 25-2 factorial design was applied to study the linear effects of the drug size, solvent to drug ratio, temperature, time and also the turbolysis speed on the extraction of glycosides. The glycosides exhaustive extraction showed that ethanol 70% gave better results and was used for turbo-extraction. The stevioside and rebaudioside A contents were quantified by a validated method by high performance liquid chromatographic with photodiode array detector. The contents of stevioside and rebaudioside A in fluid extract increased with the drug size, but decreased at high shearing speeds and solvent to drug ratio, while their yields decreased at higher temperature and were not affected by turbo speed. An increase in solvent to drug ratio reduced significantly the glycosides percent in dried extract. Optimal solution for S. rebaudiana leaves turbo-extraction was determined by desirability functions. The optimal extraction condition corresponded to drug size of 780 µm, solvent to drug ratio of 10, extraction time of 18 min; temperature of 23 ºC and turbo speed of 20,000 rpm, resulting in yields of 4.98% and 2.70%, for stevioside and rebaudioside A, respectively. These yields are comparable to the ones recently published for dynamic maceration, but with the advantage of shorter extraction times. This work demonstrates that turbolysis is promising for S. rebaudiana glycosides extraction and stimulate new research on the purification of these extracts, which may become an interesting source of income for developing countries such as India and Brazil.

Isolation and characterization of potential lactic acid bacteria (LAB) from freshwater fish processing wastes for application in fermentative utilisation of fish processing waste

Proteolytic and/or lipolytic lactic acid bacteria (LAB) were isolated from visceral wastes of different fresh water fishes. LAB count was found to be highest in case of visceral wastes of Mrigal (5.88 log cfu/g) and lowest in that of tilapia (4.22 log cfu/g). Morphological, biochemical and molecular characterization of the selected LAB isolates were carried out. Two isolates FJ1 (E. faecalis NCIM5367) and LP3 (P. acidilactici NCIM5368) showed both proteolytic and lipolytic properties. All the six native isolates selected for characterization showed antagonistic properties against several human pathogens. All the native isolates were sensitive to antibiotics cephalothin and clindamycin; and, resistant to cotrimoxazole and vancomycin. Considering individually, P. acidilactici FM37, P. acidilactici MW2 and E. faecalis FD3 were sensitive to erythromycin. The two strains FJ1 (E. faecalis NCIM 5367) and LP3 (P. acidilactici NCIM 5368) that had both proteolytic and lipolytic properties have the potential for application in fermentative recovery of lipids and proteins from fish processing wastes.

Non-Hodgkin's lymphoma of the brainstem with atrial septal mass.

Simultaneous occurrence of cardiac and central nervous system tumors have been rarely reported. A 23 years male presented to us with right cerebello-pontine (CP) angle symptoms and signs. Cranial imaging showed a mass lesion in the right pons infiltrating into the right and middle cerebellar peduncles. There was also a cardiac-atrial septal mass. The brainstem lesion was found to be a non-Hodgkin's lymphoma where as the cardiac lesion was not accessible. Central nervous system lymphomas are reported rarely and the prognosis is poor. The chances of the cardiac lesion in this patient also being a lymphoma are high, as it was a infiltrative cardiac mass, infiltrating the atrial septum.

Impact of aggressive encounters on reproductive behaviour in the Indian desert gerbil, Meriones hurricane (Jerdon).

The gerbils were exposed to daily I min aggressive encounters for 30 days, to study the effect of social stress on reproduction. The encounters were induced by introduction of an adult male or female gerbil into the cage of a male retired breeder living in isolation. In the male gerbils the encounters decreased (P < 0.001) gonadal weight and sperm counts. The accessory sex organs responded variedly to the encounters. The surface areas of abdominal scent glands decreased (P < 0.001). The results suggest that exposure to aggressive encounters had a negative influence on male reproduction in the gerbil. Contrary to the results in male gerbils, encounters with males had a positive influence on reproduction in females. This was evidenced by data on ovarian and uterine weights, follicular kinetics and the estrous cycle. The ovarian and uterine weights increased (P < 0.001) in gerbils exposed to the encounters. The number of estruses increased (P < 0.001) whereas the diestruses decreased. Study of follicular kinetics revealed an increase in the number of growing follicles and a decrease in the number of regressive follicles. The mechanism(s) by which the encounters influence reproduction is not known. Adrenal gland weights increased (P < 0.001) in both male and female gerbils exposed to the encounters. The pinealocyte cell and nuclear diameters decreased (P < 0.01) in males and increased (P < 0.001) in female gerbils after the encounters. Presumably the adrenal and pineal glands may play an important role mediating the effects of the encounters.

Role of electron beam treatment in postoperative management of carcinoma of the breast.

The aim of post operative radiotherapy to chest wall and drainage areas in advanced breast cancer is to sterilize the possible microscopic disease. Fifty cases of post surgical breast cancers were evaluated in a prospective study of chest wall radiation therapy by electrons. Fifty women of histologically proved post operative invasive breast cancers underwent simple mastectomy with axillary dissection followed by post-operative radiotherapy (Electron) to chest wall +/- drainage area. The chest wall and IMC was treated by a direct electron beam (9/12 MeV and 12 MeV) at fixed angle. 6 MV X-ray beam was used to treat axillary apex and supraclavicular area. In some cases, supplement RT was given by 6 MV X-rays through small posterior axillary portal. The energy of electron beam was 9 MeV or 12 MeV depending on the thickness of treated area. The supraclavicular and axillary lymphatic regions were treated, by direct custom shaped anterior portal. The dose delivered was 50 Gy over 5 weeks at 2 Gy per fraction. Adjuvant chemotherapy was given to patients who were pre-menopausal with histologically proved axillary node involvement as Cyclophosphamide, Methotrexate and 5-Fluorouracil (CMF) after radiotherapy. Post menopausal patients received adjuvant tamoxifen 10 mg.bid. The overall time varied from 26 to 87 days with a median of 41.5 days (SD 11.7). The followup period varied from 4-32 months with a mean of 22 months (SD 6.4). All the fifty patients developed dense pigmentation towards the end of radiation therapy, along with patchy dry desquamation. Moist desquamation occurred in 6 patients. The median OTT in the patients who developed moist desquamation was 34.5 days. The moist reaction healed over 10-15 days after completion of radiotherapy. Lung Fibrosis (Apical lobe) occurred in four patients. The fibrosis was evident at a median of 12 months of follow up. Lymphoedema of the ipsilateral arm occurred in six patients. None of 50 patients developed late sequalae like Cardiac effects, Rib fracture, Brachial Plexopathy, Shoulder joint impairement and Soft tissue effects. Local control in this study was 96% (48 patients). The two year actuarial overall survival was 80%. In early stages survival was significantly better compared to late stages. The actuarial two year DFS was 72%. In early stages DFS was significantly better compared to late stages.