Abstract
Curcumin, the bioactive component of turmeric, exhibits various pharmacological activities including anti-inflammatory, antioxidant, anticancer etc. In the present study, we examined the effect of conventional excipients on curcumin solubility tested by evaluating lipase activity. Design of experiment (DOE), created for 28 different curcumin formulations containing milk, cow milk fat, black pepper and sucrose as excipients either separately or in combination was optimized using Box-Behnken model of response surface methodology approach. This model is best fitted in ANOVA with adjusted R2 and predicted R2 value 0.9737 & 0.9284 respectively, and is significant with P < 0.0001. In addition, all formulations were also screened to find out their effect on lipase activity in-vitro. The maximum effect was observed in formulation F25 containing 0.05% curcumin, 30% milk, 1% CMF and 1% BP. In-silico studies conducted also validated the in-vitro results.
Highlights
- 28 curcumin formulations were prepared containing traditional excipients.
- In-vitro lipase activity was carried out.
- These formulations regulate the lipase activity significantly.
- Optimization by Box-behnken model which validate the results mathematically.
- Molecular docking studies support the in-vitro experimental results.
Introduction
Curcumin, an active ingredient of turmeric exists as keto-enol tautomers because of β-diketone moiety (Fig. 1) in this pharmacologically significant molecule [1]. Traditional use of turmeric in the cure of various diseases including inflammation, wound healing, cough and cold, tumour, epilepsy, haemorrhoids etc. are reported [2], [3], [4]. While going through the literature a clear gap in the systematic study of food excipients as traditionally recognized pharmacological solubilizing agents was observed. Therefore, modern proof of its clinical performance was lacking. Usually, curcumin shows low bioavailability because of low aqueous solubility of curcumin [5]. In spite of above mentioned limitations, curcumin exhibits antioxidant, anti-inflammatory, hypoglycemic, antimicrobial, antiviral, anticancer, neuroprotective, and many other effects. And, research on curcumin has increased significantly in past some decades. This may be because of shifting of paradigm from synthetic molecules to the functional foods and nutraceuticals for various health benefits. There is a need to acquire a proper scientific data with references to conventional formulations used as medicine [6], [7], [8].
We have in recent past reported the effect of different ingredients on enhanced solubility of curcumin, used in the preparation of golden milk in India. The report mentioned how presence of milk, cow milk fat (CMF), sucrose and black pepper (BP) affected the release rate kinetics of curcumin in different formulations entrapped in alginate beads, their antioxidant studies and effect of ingredients on serum protein protecting and anti-cathepsin activities [1], [9]. In continuation, the current work is focused on utilization of the Box-behnken approach of response surface methodology (RSM) with design expert software for DOE and curcumin formulation optimization/ The Box-behnken model of RSM was applied with different variables to find the optimized reaction conditions in terms of the response values of lipase activity.
Curcumin has been reported for the treatment of digestive disorders including diabetes, gastric ulcer, pulmonary diseases, allergy, obesity, hyperlipidaemia, hypertension, and other metabolic syndromes, where pancreatic lipases are directly or indirectly involved in diseased conditions [10], [11], [12], [13]. Therefore it was thought proper to scrutinize the effect of optimized and then prepared curcumin formulations on the activity of pancreatic lipase. The study not only elaborated the effect of curcumin on lipase activity but also signified the validation of pharmaceutical ingredients used in conventional medicinal systems. To achieve our motive we here report the biological activities of ingredients extracted from alginate beads as well as with the fresh formulation in liquid form toward their effect on lipase activity. Alginate beads are convenient to use and can be stored also. The results were also verified by in-silico molecular docking studies.
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Materials
Curcumin was purchased from Himedia Laboratories Pvt. Ltd. (India). Lipase from Aspergillus niger (2500 IU/mg) was supplied by LOBA Chemie Pvt. Ltd. (India). Cow milk fat was Amul make a product of Indian diary cooperative society. Pasteurized Vita double toned milk (free from sugar and trans fat), a product of Haryana Dairy Development Cooperative Federation Limited was purchased from local market. Catch SPRINKLER black pepper powder and Figaro olive oil were procured from local market.
Nitika Mor, Neera Raghav, Box–Behnken optimization of conventional excipients to examine curcumin’s effect on lipase, Pharmacological Research – Natural Products, Volume 11, 2026,100767, ISSN 2950-1997, https://doi.org/10.1016/j.prenap.2026.100767.
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