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Optimisation of extraction and sludge dewatering efficiencies of bio-flocculants extracted from Abelmoschus esculentus (okra)

Lee CS, Chong MF, Robinson J, Binner E

J Environ Manage, 2015 Jul 1;157:320-5.
PMID: 25929197 DOI: 10.1016/j.jenvman.2015.04.028

The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25-90 °C), time (0.25-5 h), solvent loading (0.5-5 w/w) and agitation speed (0-225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69-3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process.

Matched MeSH terms: Abelmoschus/chemistry*
Characterization of fibrous residues from agrowastes and the production of nanofibers

Fung WY, Yuen KH, Liong MT

J Agric Food Chem, 2010 Jul 14;58(13):8077-84.
PMID: 20568772 DOI: 10.1021/jf1012506

Oil palm trunk (OPT), oil palm frond (OPF), and okara are agrowastes generated abundantly by the palm oil and soy industries. There are vast potentials for these fibrous biomass rather than disposal at landfills or incineration. Fibrous materials (FM) and alkali-treated fibrous residues (FR) were produced from the selected wastes and subsequently characterized. Functional properties such as emulsifying properties, mineral-binding capacity, and free radical scavenging activity were also evaluated for possible development of functional products. Supernatants (FS) generated from the alkaline treatment contained soluble fractions of fibers and were also characterized and used for the production of nanofibers. Okara FM had the highest (P < 0.05) protein (31.5%) and fat (12.2%) contents, which were significantly reduced following alkali treatment. The treatment also increased total dietary fiber (TDF) in okara by 107.9%, in OPT by 67.2%, and in OPF by 25.1%. The increased fiber fractions in FR enhanced functional properties such as water-holding capacities and oil-holding capacities. Okara displayed the highest (P < 0.05) emulsifying properties compared to OPT and OPF. High IDF content of OPT and OPF contributed to high antioxidant activities (377.2 and 367.8% higher than that of okara, respectively; P < 0.05). The soluble fraction from alkali treatment of fibers was successfully electrospun into nanofibers, which can be further developed into nanoencapsulants for bioactive compound or drug delivery.

Matched MeSH terms: Abelmoschus/chemistry*
Fulltext The use of Hibiscus esculentus (Okra) gum in sustaining the release of propranolol hydrochloride in a solid oral dosage form

Zaharuddin ND, Noordin MI, Kadivar A

Biomed Res Int, 2014;2014:735891.
PMID: 24678512 DOI: 10.1155/2014/735891

The effectiveness of Okra gum in sustaining the release of propranolol hydrochloride in a tablet was studied. Okra gum was extracted from the pods of Hibiscus esculentus using acetone as a drying agent. Dried Okra gum was made into powder form and its physical and chemical characteristics such as solubility, pH, moisture content, viscosity, morphology study using SEM, infrared study using FTIR, crystallinity study using XRD, and thermal study using DSC and TGA were carried out. The powder was used in the preparation of tablet using granulation and compression methods. Propranolol hydrochloride was used as a model drug and the activity of Okra gum as a binder was compared by preparing tablets using a synthetic and a semisynthetic binder which are hydroxylmethylpropyl cellulose (HPMC) and sodium alginate, respectively. Evaluation of drug release kinetics that was attained from dissolution studies showed that Okra gum retarded the release up to 24 hours and exhibited the longest release as compared to HPMC and sodium alginate. The tensile and crushing strength of tablets was also evaluated by conducting hardness and friability tests. Okra gum was observed to produce tablets with the highest hardness value and lowest friability. Hence, Okra gum was testified as an effective adjuvant to produce favourable sustained release tablets with strong tensile and crushing strength.

Matched MeSH terms: Abelmoschus/chemistry*
Fulltext Antioxidant activity of extract and its major constituents from okra seed on rat hepatocytes injured by carbon tetrachloride

Hu L, Yu W, Li Y, Prasad N, Tang Z

Biomed Res Int, 2014;2014:341291.
PMID: 24719856 DOI: 10.1155/2014/341291

The antioxidant activities and protective effects of total phenolic extracts (TPE) and their major components from okra seeds on oxidative stress induced by carbon tetrachloride (CCl4) in rat hepatocyte cell line were investigated. The major phenolic compounds were identified as quercetin 3-O-glucosyl (1 → 6) glucoside (QDG) and quercetin 3-O-glucoside (QG). TPE, QG, and QDG from okra seeds exhibited excellent reducing power and free radical scavenging capabilities including α, α-diphenyl-β-picrylhydrazyl (DPPH), superoxide anions, and hydroxyl radical. Overall, DPPH radical scavenging activity and reducing power of QG and QDG were higher than those of TPE while superoxide and hydroxyl radical scavenging activities of QG and TPE were higher than those of QDG. Furthermore, TPE, QG, and QDG pretreatments significantly alleviated the cytotoxicity of CCl4 on rat hepatocytes, with attenuated lipid peroxidation, increased SOD and CAT activities, and decreased GPT and GOT activities. The protective effects of TPE and QG on rat hepatocytes were stronger than those of QDG. However, the cytotoxicity of CCl4 on rat hepatocytes was not affected by TPE, QG, and QDG posttreatments. It was suggested that the protective effects of TPE, QG, and QDG on rat hepatocyte against oxidative stress were related to the direct antioxidant capabilities and the induced antioxidant enzymes activities.

Matched MeSH terms: Abelmoschus/chemistry
Fulltext Double-Blind, Randomized, Three-Armed, Placebo-Controlled, Clinical Investigation to Evaluate the Benefit and Tolerability of Two Dosages of IQP-AE-103 in Reducing Body Weight in Overweight and Moderately Obese Subjects

Uebelhack R, Bongartz U, Seibt S, Bothe G, Chong PW, De Costa P, et al.

J Obes, 2019;2019:3412952.
PMID: 30863632 DOI: 10.1155/2019/3412952

OBJECTIVE: This study was performed to determine the efficacy and tolerability/safety of IQP-AE-103 on body weight reduction in overweight to moderately obese adults.
METHODS: A double-blind, randomized, placebo-controlled trial involved one hundred and eight subjects (BMI between 25 and 35 kg/m2) that were randomly assigned to either the low-dose or the high-dose IQP-AE-103 group, or the placebo group. Following a 2-week run-in period, subjects received two capsules of investigational product after three daily main meals for 12 weeks. Subjects were instructed to maintain a nutritionally balanced hypocaloric diet according to the individual's energy requirement. Body weight, body fat, and waist and hip circumference were measured at baseline, and after 2, 4, 8, and 12 weeks. Subjects also rated their feelings of hunger and fullness using visual analogue scales, and food craving on a 5-point scale at the same time intervals. Blood samplings for safety laboratory parameters were taken before and at the end of the study.
RESULTS: After 12 weeks of intake, the high-dose IQP-AE-103 group had a significantly greater weight loss compared with the placebo (5.03 ± 2.50 kg vs. 0.98 ± 2.06 kg, respectively; p < 0.001) and the low-dose group (3.01 ± 2.19 kg; p=0.001). The high-dose group experienced a decrease in body fat of 3.15 ± 2.41 kg compared with a decrease of 0.23 ± 2.74 kg for the placebo group (p < 0.001). High-dose IQP-AE-103 also decreased the feeling of hunger in 66% subjects. A beneficial effect of IQP-AE-103 on the lipid metabolism was also demonstrated in the subgroup of subjects with baseline total cholesterol levels above 6.2 mmol/L. No side effects related to the intake of IQP-AE-103 were reported.
CONCLUSIONS: These findings indicate that IQP-AE-103 could be an effective and safe weight loss intervention. This trial is registered with NCT03058367.

Matched MeSH terms: Abelmoschus/chemistry