Abstract : Temperature-dependent solubility data of bioactive compound hesperidin has not been reported in any solvent in the literature so far. Therefore, the aim of the current study was to measure the solubility of bioactive compound hesperidin in six different pure solvents namely water, ethanol, isopropyl alcohol (IPA), propylene glycol (PG), poly(ethylene glycol)-400 (PEG-400), and 1-butanol from (298.15 to 333.15) K using the shake flask method. The experimental solubilities of hesperidin were regressed by Apelblat equation with root-mean-square deviations in the range of 6.32·10−7 to 0.184 in all solvents investigated. The correlation coefficients in pure solvents were observed in the range of 0.995 to 0.999. The mole fraction solubility of hesperidin was found to be higher in PEG-400 (6.33·10−3 at 298.15 K) and PG (5.35·10−4 at 298.15 K) as compared to water (1.47·10−7 at 298.15 K), ethanol (3.45·10−5 at 298.15 K), IPA (1.53·10−5 at 298.15 K), and 1-butanol (3.15·10−4 at 298.15 K). The data of the current study could be useful in crystallization/ purification and formulation development of hesperidin in the chemical/ pharmaceutical industry.
Conclusion : In the present study, the solubility of bioactive compound hesperidin in six different pure solvents namely water, ethanol, IPA, PG, PEG-400, and 1-butanol were measured at (298.15 to 333.15) K. The solubility of bioactive compound hesperidin was found to be increased with temperature in all solvents investigated. The solubility of hesperidin was significantly higher in PEG-400 and PG as compared to water, ethanol, IPA, and 1-butanol. The experimental solubilities of hesperidin were correlated well with the Apelblat equation in all solvents from (298.15 to 333.15) K with the correlation coefficients of 0.995 to 0.999. Based on these results, hesperidin has been considered as practically insoluble in water; poorly soluble in ethanol, IPA, and 1-butanol; and soluble in PEG-400 and PG. The data of current study could be useful in crystallization/ purification and formulation development of bioactive compound hesperidin.
Solubility of Bioactive Compound Hesperidin in Six Pure Solvents at (298.15 to 333.15) K - Md Khalid Anwer, Ramadan Al-Shdefat, Shahid Jamil, Prawez Alam, Maged S. Abdel-Kader and Faiyaz Shakeel

Purpose. Hesperidin holds potential in treating age-related macular degeneration, cataract and diabetic retinopathy. The aim of this study, constituting the first step towards efficient ocular delivery of hesperidin, was to determine its physicochemical properties and in vitro ocular tissue permeability.
Methods. pH dependent aqueous solubility and stability were investigated following standard protocols. Permeability of hesperidin across excised rabbit cornea, sclera, and sclera plus retinal pigmented epithelium (RPE) was determined using a side-bi-side diffusion apparatus.
Results. Hesperidin demonstrated poor, pH independent, aqueous solubility. Solubility improved dramatically in the presence of 2- hydroxypropyl- beta- cyclodextrin (HP-β-CD) and the results supported 1:1 complex formation. Solutions were stable in the pH and temperature (25, 40°C) conditions tested, except for samples stored at pH 9. Transcorneal permeability in the apical-basal and basal-apical directions was 1.11±0.86×10−6 and 1.16±0.05×10−6 cm/s, respectively. The scleral tissue was more permeable (10.2±2.1×10−6 cm/s). However, permeability across sclera/choroid/RPE in the sclera to retina and retina to sclera direction was 0.82±0.69×10−6, 1.52±0.78×10−6 cm/s, respectively, demonstrating the barrier properties of the RPE.
Conclusion. Our results suggest that stable ophthalmic solutions of hesperidin can be prepared and that hesperidin can efficiently permeate across the corneal tissue. Further investigation into its penetration into the back-of-the eye ocular tissues is warranted.
Solubility, Stability, Physicochemical Characteristics and In Vitro Ocular Tissue Permeability of Hesperidin: A Natural Bioflavonoid - Soumyajit Majumdar and Ramesh Srirangam - Pharmaceutical Research, Vol. 26, No. 5, May 2009 (# 2008)

Abstract Previous studies have shown that polyphenol supplementation may be an effective strategy to improve exercise performance, due to their antioxidant character and ability to stimulate NO production. These properties may contribute to exercise perfor-mance, yet no conclusive research has been performed in ex-ploring the direct effects of citrus flavonoids on human exercise performance. Therefore, the purpose of this study was to assess whether supplementation of a customized citrus flavonoid (CF) extract for 4 weeks improves cycling time-trial performance in trained male athletes. In a double-blind, randomized, parallel study, 39 healthy, trained males were given a daily dose of either 500 mg of a customized citrus flavonoid extract (CF) or a placebo for 4 weeks. Exercise performance was tested by means of a time-trial test on a cycle ergometer, during which partici-pants had to generate as much power as possible for duration of 10 minutes. Absolute power output significantly increased with 14.9 ± 3.9 W after 4 weeks of CF supplementation, correspond-ing with a 5.0% increase, compared to 3.8 ± 3.2 W (1.3% in-crease) in placebo (p < 0.05). In addition, oxygen consump-tion/power ratio significantly decreased in the CF group com-pared to placebo (p = 0.001), and a trend was found in the change in peak power output in CF (18.2 ± 23.2 W) versus placebo (-28.4 ± 17.6 W; p = 0.116). The current study is the first convincing report that citrus flavonoid supplementation can improve exercise performance, as shown by a significant in-crease in power output during the exercise test.
Key words: Hesperetin, power output, antioxidant, time trial, ergometer
Citrus Flavonoid Supplementation Improves Exercise Performance in Trained Athletes Elvera Overdevest, Jeroen A. Wouters, Kevin H.M. Wolfs, Job J.M. van Leeuwen and Sam Possemiers - Journal of Sports Science and Medicine (2018) 17, 24-30

Abstract : 2S-Hesperidin is the main flavonoid of orange (Citrus sinensis). Previous researches have pointed its effects in muscle development and fat accumulation reduction, although most of these results have not been assessed in humans. The objective of this study is to evaluate the effect of chronic (8-weeks) intake of 2S-hesperidin on amateur cyclists' body composition. A double-blind, parallel and randomized trial, was carried out with 40 amateur cyclists that were divided in two groups, one taking 2S-hesperidin (500 mg d-1, n = 20) and another taking placebo (500 mg d-1 microcellulose, n = 20) for 8 weeks. Dual-energy X-ray absorptiometry (DXA) and anthropometric measurements were used to assess the effect of both treatments on body composition. In addition, the resting metabolic rate was measured. In comparison to placebo, DXA analysis showed a decrease in percentage body fat (%BF) (-10.4%; p = 0.035) and lower limb fat mass (-10.5%; p = 0.029) in favour of 2S-hesperidin. After evaluation of anthropometric data, a decrease in %BF (-3.7%; p = 0.006), total body fat (-3.0%; p = 0.047), ∑ of 8 skinfolds (-6.1%; p = 0.008) was observed in 2S-hesperidin group, but not in placebo. Additionally, there was an increase in muscle mass percentage (1.0%; p = max 0.001) and total muscle mass (1.7%; p = 0.011) after ingestion of 2S-hesperidin, with no changes in placebo. Chronic intake of 2S-hesperidin decreased fat mass in amateur cyclists, evaluated through different body composition measurement methodologies (DXA and anthropometry). In addition, 2S-hesperidin supplementation showed a promoting effect on muscle development.
8 weeks of 2 S-Hesperidin supplementation improves muscle mass and reduces fat in amateur competitive cyclists: randomized controlled trial, Francisco Javier Martínez Noguera, Pedro E Alcaraz, Jorge Carlos Vivas, Linda H Chung, Elena Marín Cascales, Cristian Marín Pagán