Introduction: Ocimum basilicum (OB), a herb known for its antihypertensive,
anticholinesterase and antioxidant properties was investigated for possible intraocular
pressure (IOP) lowering effects in rabbits with ocular hypertension (OHT). Methods: The
IOP lowering effect of a single drop of OB extract (OBE) was evaluated in oculonormotensive
rabbits using three concentrations (0.25, 0.5 and 1% w/v). The concentration showing
maximum IOP reduction was further evaluated in rabbits with water-loading and steroidinduced OHT. Results: IOP lowering effect of OBE 0.5% in oculonormotensive rabbit eyes
was significantly greater compared to OBE 0.25% (p0.05) to
OBE 1%. Therefore, 0.5% concentration was selected for further evaluation. Pretreatment
with OBE (0.5%) caused significantly lower increase in IOP after water loading amounting to
23.39% above baseline as compared to 54.00% in control eye, 15 minutes post water
loading. At 60 minutes, post water loading, mean IOP rise was 95.12% and 63.58% in
control and test eyes, respectively. Significant difference between the mean IOP of two eyes
persisted during the 2nd hr. In rabbits with steroid induced OHT, OBE 0.5% produced a
mean IOP reduction of 24.73% at the end of first hr and the mean peak IOP reduction of
31.63% was observed at the end of 2 hr. A significant difference between the IOP of test and
control eyes persisted from 1 to 6 hr. Conclusions: Ocimum basilicum seed extract showed
significant IOP lowering effect in rabbits with water loading and steroid induced OHT,
however, its utility as an effective antiglaucoma medication needs further investigations.
Glaucoma is an optic neuropathy characterised by optic nerve degeneration associated with
visual field defects. It remains the world’s number one cause of irreversible blindness and
patients usually present at late stage of the disease since it is generally asymptomatic until
severe. The disease is subdivided into primary and secondary with primary open-angle
glaucoma (POAG) being the most common type. At present, lowering the intraocular pressure
(IOP) remains the only proven efficient approach in delaying the onset or preventing the
progression of the disease. Medical treatment with topical antiglaucoma agents is the
treatment of choice in open angle glaucoma. The use of antiglaucoma drugs aims to reduce
IOP by enhancing aqueous humour (AH) outflow, reducing AH production, or both. The choice
to use any available treatment option should be carefully considered in an attempt to maximise
benefits and reducing the risk of developing adverse drug reactions. This review highlights the
six classes of ocular hypotensive agents currently in use for POAG treatment including
prostaglandin analogues; -adrenergic receptor blockers; -2 adrenergic receptor stimulants;
carbonic anhydrase inhibitors; muscarinic receptor stimulants; rho kinase inhibitors with
regards to their mechanism/s of action and potential adverse drug reactions, and
antiglaucoma fixed drug combinations.
Introduction: This study examined the association of losartan induced changes in urinary
metabolomic profile with the changes in blood pressure (BP) and renin-angiotensinaldosterone system (RAAS) in spontaneously hypertensive rats (SHR). Methods: Male SHR
were administered with either 0.5 mL of distilled water (control group, n=6) or 10 mg.kg-1 of
losartan (group 2, n=6) daily by oral gavage for 4 weeks. Body weight, BP, food and water
intake were measured weekly. At week 4, urine was collected for urinary electrolyte analysis
and metabolite profiling, after which the animals were euthanised by decapitation and blood
was collected for analysis of components of RAAS and electrolyte concentrations. Urine
metabolite profile of SHR was determined using proton nuclear magnetic resonance (
1H-NMR)
spectrometry combined with multivariate data analysis. Results: At week 4, losartan-treated
SHR had significantly lower BP than non-treated SHR. There were no differences in water
and food intake, body weight, serum and urinary electrolyte concentrations or in their urinary
excretions between the two groups. No differences were evident in the components of RAAS
except that the angiotensinogen level was significantly higher in losartan-treated SHR
compared to non-treated SHR. Orthogonal partial least squares discriminant analysis (OPLSDA) showed clear separation of urinary metabolites between control and losartan-treated
SHR. Losartan-treated SHR group was separated from the control group by changes in the
intermediates involved in glycine, serine and threonine metabolism. Conclusion:
Antihypertensive effect of losartan in SHR seems to be associated with changes in urinary
metabolite profile, particularly involving the metabolism of glycine, serine and threonine.