Saima Khaliq

Repeated Administration of Fresh Garlic Increases Memory Retention in Rats

Garlic (Allium sativum) is regarded as both a food and a medicinal herb. Increasing attention has focused on the biological functions and health benefits of garlic as a potentially major dietary component. Chronic garlic administration has been shown to enhance memory function. Evidence also shows that garlic administration in rats affects brain serotonin (5-hydroxytryptamine [5-HT]) levels. 5-HT, a neurotransmitter involved in a number of physiological functions, is also known to enhance cognitive performance. The present study was designed to investigate the probable neurochemical mechanism responsible for the enhancement of memory following garlic administration. Sixteen adult locally bred male albino Wistar rats were divided into control (n = 8) and test (n = 8) groups. The test group was orally administered 250 mg/kg fresh garlic homogenate (FGH), while control animals received an equal amount of water daily for 21 days. Estimation of plasma free and total tryptophan (TRP) and whole brain TRP, 5-HT, and 5-hydroxyindole acetic acid (5-HIAA) was determined by high-performance liquid chromatography with electrochemical detection. For assessment of memory, a step-through passive avoidance paradigm (electric shock avoidance) was used. The results showed that the levels of plasma free TRP significantly increased (P < .01) and plasma total TRP significantly decreased (P < .01) in garlic-treated rats. Brain TRP, 5-HT, and 5-HIAA levels were also significantly increased following garlic administration. A significant improvement in memory function was exhibited by garlic-treated rats in the passive avoidance test. Increased brain 5-HT levels were associated with improved cognitive performance. The present results, therefore, demonstrate that the memory-enhancing effect of garlic may be associated with increased brain 5-HT metabolism in rats. The results further support the use of garlic as a food supplement for the enhancement of memory.

Sargassum swartzii extracts ameliorate memory functions by neurochemical modulation in a rat model

Recently, considerable attention has been paid to drug exploration from natural sources for treating memory loss, a major manifestation of various neurodegenerative diseases. Increasing evidences implicate brain serotonin metabolism in learning and memory, supporting the notion that targeting 5-HT (5-hydroxytryptamine) and its receptors would be beneficial in the treatment of cognitive disorders. In the present study, behavioral and neurochemical effects were examined following administration of Sargassum swartzii extracts in albino Wistar rats. Increase in spatial working memory and recognition memory was exhibited by the seaweed-treated rats as compared to controls. Plasma tryptophan, brain 5-HT, and 5-hydroxyindoleacetic acid levels were measured using HPLC–ECD, and a significant increase in brain 5-HT metabolism was observed in the seaweed-treated rats. The increase in memory functions following repeated administration of S. swartzii extracts is suggested to be due to the increased serotonergic neurotransmission in the brain of seaweed-treated rats.

Antidepressant-like deliverables from the sea: evidence on the efficacy of three different brown seaweeds via involvement of monoaminergic system

Brown seaweeds exhibit several health benefits in treating and managing wide array of ailments. In this study, the antidepressant-like effect of methaolic extracts from Sargassum swartzii (SS), Stoechospermum marginatum (SM), and Nizamuddinia zanardinii (NZ) was examined in forced swimming test (FST), in rats. Oral administration of SS, SM, and NZ extract (30–60 mg/kg) exhibited antidepressant-like activity in FST by reducing immobility time as compared to control group, without inducing significant change in ambulatory behavior in open field test. In order to evaluate the involvement of monoaminergic system, rats were pretreated with the inhibitor of brain serotonin stores p-chlorophenylalanin (PCPA), dopamine (SCH23390 and sulpiride), and adrenoceptor (prazosin and propranolol) antagonists. Rats receiving treatment for 28 days were decapitated and brains were analyzed for monoamine levels. It may be concluded that the extracts of SS, SM, and NZ produces antidepressant-like activity via modulation of brain monoaminergic system in a rat model. Antidepressant-like activities of selected brown seaweeds via modulation of monoaminergic system.

Greater Prevalence of Depression in Type I Diabetic Patients: Correlation with Decreased Plasma Tryptophan

The present study was designed to determine the frequency of major and minor depression in type I Diabetes and to relate the occurrence of depression with plasma tryptophan levels. Study was conducted during the period January 2011 to September 2011 at two private hospitals of North Nazimabad in Karachi; Hanif hospital and Haleem hospital. 100 diabetic subjects were selected out of which 50 were males and 50 were females. Likewise the controls were also in the same number. Patients with type II diabetes mellitus and hypertension were excluded from the study. The study was done to evaluate major and minor depression in diabetic and control subjects. Blood samples from all the participants were collected in fasting from anticubital vein to determine plasma TRP levels. Plasma TRP levels were measured by HPLC-UV method. Our data showed that among the control male subjects 5% were having minor depression while 95% were with no depression, while among test subjects 34% were having major depression, 66% were with minor symptoms of depression. However, among the female controls 13% were suffering with minor depression while 87% were with no depression. Among the female test subjects, 50% were having major depression and 50% were having minor depression. Present study showed a significant (p<0.01) decrease in plasma tryptophan levels in both male and female diabetic patients as compared to healthy non-diabetic controls. The present finding suggests that frequency of major and minor depression is increased in diabetes. Present findings indicate that decreased plasma TRP levels and lowered brain 5-HT levels may be responsible for depression seen in diabetics.