Sea Buckthorn (Hippophae rhamnoides) Waste Biomass after Harvesting as a Source of Valuable Biologically Active Compounds with Nutraceutical and Antibacterial Potential

Funding Information: Funding: This research was funded by ERDF project nr. Nr.1.1.1.1/19/A/146 “Biorefinery processing of sea buckthorn non-fruit biomass using innovative techniques and comprehensive analytical investigation, for obtaining prospective for Latvian bioeconomy high value-added products, including serotonin”. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.For sustainable sea buckthorn (Hippophae rhamnoides) berry production, the task at hand is to find an application for the large amount of biomass waste arising at harvesting. Sea buckthorn (SBT) vegetation is currently poorly studied. The purpose of this research was to assess the composition and potential of SBT twigs as a source of valuable biologically active substances. Water and 50% EtOH extracts of twigs of three Latvian SBT cultivars with a high berry yield and quality, popular for cultivation in many countries (H. rhamnoides ‘Maria Bruvele', ‘Tatiana', ‘Botanicheskaya Lubitelskaya'), were investigated for the first time. The phytochemical composition (UHPLC-ESI-MS/MS analysis) and biological activity of the obtained hydrophilic extracts were determined. The highest yield of polyphenolic compounds and serotonin was observed for ‘Maria Bruvele'. Hydrophilic extracts were investigated for radical scavenging activity (DPPH' test), antibacterial/antifungal activity against five pathogenic bacteria/yeast, cytotoxicity, and the enzymatic activity of alpha-amylase (via in vitro testing), which is extremely important for the treatment of people with underweight, wasting, and malabsorption. The results showed a high potential of sea buckthorn biomass as a source of valuable biologically active compounds for the creation of preparations for the food industry, nutraceuticals, and cosmetics.publishersversionPeer reviewe

A Comparative Assessment of Sea Buckthorn (Hippophae rhamnoides L.) Pruning Waste as a Potential Source of Serotonin

Sea buckthorn (Hippophae rhamnoides L.) twigs, remaining after harvesting and pruning, are an underutilized and little-explored biomass resource. This study investigated the content of serotonin in 10 sea buckthorn cultivars (‘Maria Bruvele’, ‘Botanicheskaya Lubitelskaya’, ‘Tatiana’, ‘Otto’, ‘Leikora’, ‘Duet’, ‘Clara’, ‘Lord’, ‘Eva’, ‘Tarmo’) for the first time, and for further adjustment of the extraction conditions, cultivar ‘Maria Bruvele’ was extracted by water and water/ethanol solution with 20-25, 50, 70, and 96% ethanol at different temperatures. The results showed that 50% water/ethanol solutions are the most suitable for extraction, which makes it possible to increase the yield of serotonin. The 2-year-old twigs and bark from ‘Maria Bruvele’ collected in autumn contained higher serotonin content compared to spring-collected biomass. Serotonin sequential purification allowed the serotonin content in the fraction to increase to 26%/DM. The serotonin-rich fraction showed antimicrobial activity against gram-positive and gram-negative bacteria. In tests with salivary amylase, a serotonin-rich fraction at the amount of 0.1-0.4 mg/mL of saliva, under normal physiological conditions, tended to increase amylase activity, resulting in acceleration of starch degradation to glucose. Thus, the results support further study of the serotonin fraction for the treatment of people having underweight, malnutrition, and malabsorption conditions

Lignocellulosic Waste Compounds for Pancreatic Lipase Inhibition: Preliminary Extraction by Freon, Obtaining of Proanthocyanidins and Testing on Lipase Activity

The twigs of sea buckthorn, blackcurrant, gooseberries, quince, and grapes were evaluated as a promising source of biologically active compounds—proanthocyanidins (PACs). Sea buckthorn twigs had the highest content of PACs (9.2% on dry biomass). Preliminary pretreatment of biomass with freon R134a did not allow an increase in PACs content in the composition of hydrophilic extract but confirmed the value of freon extract as an antibacterial agent against P. aeruginosa and B. cereus. The content of PACs was used as an indicator for assessment of the influence of hydrophilic extracts on pancreatic lipase activity. Under normal physiological conditions, in the presence of bile, the extract, which contained 42.4% of PACs was more effective compared to the extract which contained 17.5% of PACs. At all concentrations (0.2–40 mg of sample/g of pancreatic lipase), it inhibited lipase activity by 33%. Purified PACs were the most effective in inhibiting lipase activity (by 36%). However, in pathological physiological conditions (without bile), the opposite effect on lipase activity was observed. Thus, PACs and extracts can be used as inhibitors of pancreatic lipase only under normal physiological conditions

Anti-Inflammatory, Anti-Bacterial, and Anti-Fungal Activity of Oligomeric Proanthocyanidins and Extracts Obtained from Lignocellulosic Agricultural Waste

It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs’ functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar ‘Maria Bruvele’ in the concentration range 0.0313–4.0 mg/mL, no toxic effect was observed

Granulated Animal Feed and Fuel Based on Sea Buckthorn Agro-Waste Biomass for Sustainable Berry Production

Funding Information: This work was financially supported by the ERDF project no. 1.1.1.1/19/A/146 “Biorefinery processing of sea buckthorn non-fruit biomass using innovative techniques and comprehensive analytical investigation, for obtaining prospective high value-added products for the Latvian bioeconomy, including serotonin”. Publisher Copyright: © 2023 by the authors.The industrial harvesting of sea buckthorn (SBT) berries with twigs and subsequent pruning creates a large volume of lignocellulosic agro-waste. This study aimed to valorize this agro-waste as a raw material for animal feed and fuel granules, for developing a sustainable cascading SBT production scheme. Five SBT cultivars’ biomasses were characterized by analytical pyrolysis, mass spectrometry, and GC analysis. Condensed tannins, which are undesirable components for animal feed, were separated by extraction. The residue was analyzed for total protein, vitamins (A, C, and E), ash, crude fat, wood fiber, and macroelements (P, K, Ca, and Na), and showed great potential. The heavy metal (Cd, Hg, and Pb) content did not exceed the permitted EU maximum. Granulation regimes were elaborated using a flat-die pelletizer, KAHL 14-175. The digestibility and the amount of produced gas emissions were determined using in vitro systems that recreate the digestion of small ruminants. The investigation proved that SBT leaves and stems are a unique underutilized source of animal feed, used alone or in combination with others. Twigs, due to their thorns, were granulated and valorized according to standards for application as fuel. The scheme offered in this study enables SBT agro-waste utilization and sustainable SBT berry production.Peer reviewe

Eco-Friendly Adhesives Based on the Oligomeric Condensed Tannins-Rich Extract from Alder Bark for Particleboard and Plywood Production

Toxic formaldehyde emissions, and the necessity to reduce the consumption of petrochemicals, stimulates the development of environmentally friendly adhesives. The aim of this research was to study, for the first time, the possibility of using condensed tannins (CTs)-rich extracts from grey alder (Alnus incana) and black alder (Alnus glutinosa) bark in the production of particleboards and plywood adhesives. The chemical structure, composition, and molecular weight of the CTs were identified by a 13C-NMR and TOF-MS analysis. Three innovative adhesive systems were studied: CTs-phenol-formaldehyde (CTs-PF) resin; a CTs-polyethyleneimine (PEI) adhesive system; and CTs–PEI combined with an ultra-low emitting formaldehyde resin (ULEFR)—CTs–PEI–ULEFR. The results showed that CTs-PF resin has properties close to commercial PF resin, and the formaldehyde emission was twice lower. CTs–PEI bonded particleboards corresponded to the requirements of the EN 312:2010 standard for particleboards in dry conditions (Type P2). CTs–PEI–ULEFR, with a 40–60% substitution of ULEFR by CTs–PEI, had adhesive properties very close to ULEFR; the plywood shear strength fit the requirements of the EN 314-2:1993 standard for application in internal and external system conditions. The introduction of extracted alder bark residues microparticles into the composition of the adhesive system showed their positive potential for application as a filler