Highly clean recovery of natural antioxidants from lemon peels: Lactic acid-based automatic solvent extraction

Optimisation of enzyme-assisted extraction of camptothecin from Nothapodytes nimmoniana and its characterisation

INTRODUCTION

Efficient extraction of camptothecin (CPT), an anticancer agent from the commercial source Nothapodytes nimmoniana (J. Graham) Mabb in India, is of paramount importance. CPT is present in the highest concentration in the stem portion, and the stem can be readily harvested without uprooting the plant. The fluorescence microscopy mapping of the bark matrix for CPT revealed its presence in a free form within both the outer (epidermal and cortical tissues) and inner (xylem and phloem tissues) sections. The bark matrix primarily consists of cellulose, hemicellulose, and lignin, rendering it woody, rigid, and resistant to efficient solvent penetration for CPT extraction. We proposed a hypothesis that subjecting it to disruption through treatment with hydrolytic enzymes like cellulase and xylanase could enhance solvent diffusion, thereby enabling a swift and effective extraction of CPT.

OBJECTIVE

The present study was aimed at enzyme-assisted extraction, using cellulase and xylanase for hydrolytic disruption of the cells to readily access CPT from the stem of the plant N. nimmoniana (J. Graham) Mabb.

METHODOLOGY

The hydrolytic cell disruption of ground powder from the stem bark was studied using cellulase and xylanase enzymes. The enzymatically pretreated stem bark powder was subsequently recovered by filtration, dried, and subjected to extraction with methanol to isolate CPT. This process was optimised through a Box-Behnken design, employing a one-factor-at-a-time approach to assess parameters such as enzyme concentration (2-10% w/w), pH (3-7), incubation time (6-24 h), and solid-to-solvent ratio (1:30-1:70 g/mL). CPT was characterised using proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectra, and a high-performance liquid chromatography (HPLC) method was developed for quantification.

RESULTS

The cellulase and xylanase treatment resulted in the highest yields of 0.285% w/w and 0.343% w/w, with efficiencies of 67% and 81%, respectively, achieved in a significantly shorter time compared to the untreated material, which yielded 0.18% with an efficiency of only 42%. Extraction by utilising the predicted optimised process parameters, a nearly two-fold increase in the yield, was observed for xylanase, with incubation and solvent extraction times set at 16 and 2 h, respectively. Scanning electron microscopy (SEM) images of the spent material indicated perforations attributed to enzymatic action, suggesting that this could be a primary factor contributing to the enhanced extraction.

CONCLUSION

Enzyme-mediated hydrolytic cell disruption could be a potential approach for efficient and rapid isolation of CPT from the bark of N. nimmoniana.

Unveiling the Chemistry of Citrus Peel: Insights into Nutraceutical Potential and Therapeutic Applications

The recent millennium has witnessed a notable shift in consumer focus towards natural products for addressing lifestyle-related disorders, driven by their safety and cost-effectiveness. Nutraceuticals and functional foods play an imperative role by meeting nutritional needs and offering medicinal benefits. With increased scientific knowledge and awareness, the significance of a healthy lifestyle, including diet, in reducing disease risk is widely acknowledged, facilitating access to a diverse and safer diet for longevity. Plant-based foods rich in phytochemicals are increasingly popular and effectively utilized in disease management. Agricultural waste from plant-based foods is being recognized as a valuable source of nutraceuticals for dietary interventions. Citrus peels, known for their diverse flavonoids, are emerging as a promising health-promoting ingredient. Globally, citrus production yields approximately 15 million tons of by-products annually, highlighting the substantial potential for utilizing citrus waste in phyto-therapeutic and nutraceutical applications. Citrus peels are a rich source of flavonoids, with concentrations ranging from 2.5 to 5.5 g/100 g dry weight, depending on the citrus variety. The most abundant flavonoids in citrus peel include hesperidin and naringin, as well as essential oils rich in monoterpenes like limonene. The peel extracts exhibit high antioxidant capacity, with DPPH radical scavenging activities ranging from 70 to 90%, comparable to synthetic antioxidants like BHA and BHT. Additionally, the flavonoids present in citrus peel have been found to have antioxidant properties, which can help reduce oxidative stress by 30% and cardiovascular disease by 25%. Potent anti-inflammatory effects have also been demonstrated, reducing inflammatory markers such as IL-6 and TNF-α by up to 40% in cell culture studies. These findings highlight the potential of citrus peel as a valuable source of nutraceuticals in diet-based therapies.

Flavonoid Extracts from Lemon By-Products as a Functional Ingredient for New Foods: A Systematic Review

This systematic review seeks to highlight, from the published literature about the extraction and application of lemon by-products rich in flavonoids, which works use environmentally friendly technologies and solvents and which ones propose a potentially functional food application, according to the Sustainable Development Goals (SDGs). WoS and SCOPUS were used as scientific databases for searching the documents, which were evaluated through 10 quality questions according to their adherence to our purpose (5 questions evaluating papers devoted to lemon flavonoid extraction and 5 concerning the application of such by-products in new foods). Each question was evaluated as "Yes", "No", or "does Not refer", according to its adherence to our aim. The analysis reported 39 manuscripts related to lemon flavonoid extraction; 89% of them used green technologies and solvents. On the other hand, 18 manuscripts were related to the incorporation of lemon by-products into new foods, of which 41% adhered to our purpose and only 35% evaluated the functionality of such incorporation. Conclusively, although the bibliography is extensive, there are still some gaps for further investigation concerning the extraction and application of lemon by-products to reduce food losses in an environmentally friendly way and the possible development of new functional foods, which must be performed following the SDGs.

Synthesis of hexyl butyrate (apple and citrus aroma) by Candida rugosa lipase immobilized on Diaion HP-20 using the Box-Behnken design

This study aims at the synthesis of hexyl butyrate by Candida rugosa lipase (CRL) immobilized on Diaion HP 20. The lipase load used was 28.7 ± 2.1 mg/g (mg of lipase/g of support), whose hydrolytic activity was 132.0 ± 2.5 U/g. To obtain the maximum production of hexyl butyrate, the Box-Behnken design statistical planning was used, having as independent variables; biocatalyst concentration, temperature and acid:alcohol molar ratio and ester conversion as a dependent variable at 60, 180 and 480 min. For 60 min, 90.8% conversion was obtained at 47.25 ºC, 1:1.4 molar ratio and 17.65% of biocatalyst; 180 min, 94.5% conversion at 59.5 ºC, 1:2 molar ratio and 15.8% biocatalyst; 480 min, 95.01% conversion at 47.0 ºC, 1:2 molar ratio and 16.9% biocatalyst. CRL-Diaion HP 20 retained 60% of its initial activity after ten cycles of reactions showing potential for industrial use. The ester produced was identified by gas chromatography analyses.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01200-1.

Development of an Encapsulation Method for Trapping the Active Materials from Sour Cherry Biowaste in Alginate Microcapsules

This study aims to contribute to those valorization approaches for the recovery process of high-value-added substances in environmentally friendly ways. In this study, one of the most consumed juice products was selected for providing waste byproducts (peel). Sour cherry peels were subjected to automatic solvent extraction using a GRAS solvent (aqueous 80% ethanol, v/v). Then, encapsulation for the preservation of the related extract was performed by ionic gelation in alginate beads. The process conditions (gelling medium concentration, wall material concentration, and hardening time) were optimized by a Box-Behnken design (statistical experimental design approach). An almost 80% encapsulation efficiency was achieved under the proposed method (7.8% CaCI₂, 1.3% alginate, and 26 min). The inhibition effect of the produced capsules against DPPH (2,2-diphenyl-1-picrylhydrazil) radicals also shows that the current products might represent potential alternative natural antioxidants for food formulations. The morphological properties were also measured.