Conversion of Squid Pen to Homogentisic Acid via Paenibacillus sp. TKU036 and the Antioxidant and Anti-Inflammatory Activities of Homogentisic Acid

Exploring natural microbial resources for the discovery of anti-malarial compounds

Microorganisms in nature are highly diverse biological resources, which can be explored for drug discovery. Some countries including Brazil, Columbia, Indonesia, China, and Mexico, which are blessed with geographical uniqueness with diverse climates and display remarkable megabiodiversity, potentially provide microorganismal resources for such exploitation. In this review, as an example of drug discovery campaigns against tropical parasitic diseases utilizing microorganisms from such a megabiodiversity country, we summarize our past and on-going activities toward discovery of new antimalarials. The program was held in a bilateral collaboration between multiple Indonesian and Japanese research groups. In order to develop a new platform of drug discovery utilizing Indonesian bioresources under an international collaborative scheme, we aimed at: 1) establishment of an Indonesian microbial depository, 2) development of robust enzyme-based and cell-based screening systems, and 3) technology transfer necessary for screening, purification, and identification of antimalarial compounds from microbial culture broths. We collected, characterized, and deposited Indonesian microbes. We morphologically and genetically characterized fungi and actinomycetes strains isolated from 5 different locations representing 3 Indonesian geographical areas, and validated genetic diversity of microbes. Enzyme-based screening was developed against two validated mitochondrial enzymes from Plasmodium falciparum, dihydroorotate dehydrogenase and malate:quinone oxidoreductase, while cell-based proliferation assay was developed using the erythrocytic stage parasite of 3D7 strain. More than 17 thousands microbial culture extracts were subjected to the enzyme- and cell-based screening. Representative anti-malarial compounds discovered in this campaign are discussed, including a few isolated compounds that have been identified for the first time as anti-malarial compounds. Our antimalarial discovery campaign validated the Indonesian microbial library as a powerful resource for drug discovery. We also discuss critical needs for selection criteria for hits at each stage of screening and hit deconvolution such as preliminary extraction test for the initial profiling of the active compounds and dereplication techniques to minimize repetitive discovery of known compounds.

Metabolomes and Lipidomes of the Infective Stages of the Gastrointestinal nematodes, Nippostrongylus brasiliensis and Trichuris muris

Soil-transmitted helminths, including hookworms and whipworms, infect billions of people worldwide. Their capacity to penetrate and migrate through their hosts’ tissues is influenced by the suite of molecules produced by the infective developmental stages. To facilitate a better understanding of the immunobiology and pathogenicity of human hookworms and whipworms, we investigated the metabolomes of the infective stage of Nippostrongylus brasiliensis third-stage larvae (L3) which penetrate the skin and Trichuris muris eggs which are orally ingested, using untargeted liquid chromatography-mass spectrometry (LC-MS). We identified 55 polar metabolites through Metabolomics Standard Initiative level-1 (MSI-I) identification from N. brasiliensis and T. muris infective stages, out of which seven were unique to excretory/secretory products (ESPs) of N. brasiliensis L3. Amino acids were a principal constituent (33 amino acids). Additionally, we identified 350 putative lipids, out of which 28 (all known lipids) were unique to N. brasiliensis L3 somatic extract and four to T. muris embryonated egg somatic extract. Glycerophospholipids and glycerolipids were the major lipid groups. The catalogue of metabolites identified in this study shed light on the biology, and possible therapeutic and diagnostic targets for the treatment of these critical infectious pathogens. Moreover, with the growing body of literature on the therapeutic utility of helminth ESPs for treating inflammatory diseases, a role for metabolites is likely but has received little attention thus far.

Production and Potential Applications of Bioconversion of Chitin and Protein-Containing Fishery Byproducts into Prodigiosin: A Review

The technology of microbial conversion provides a potential way to exploit compounds of biotechnological potential. The red pigment prodigiosin (PG) and other PG-like pigments from bacteria, majorly from Serratia marcescens, have been reported as bioactive secondary metabolites that can be used in the broad fields of agriculture, fine chemicals, and pharmacy. Increasing PG productivity by investigating the culture conditions especially the inexpensive carbon and nitrogen (C/N) sources has become an important factor for large-scale production. Investigations into the bioactivities and applications of PG and its related compounds have also been given increased attention. To save production cost, chitin and protein-containing fishery byproducts have recently been investigated as the sole C/N source for the production of PG and chitinolytic/proteolytic enzymes. This strategy provides an environmentally-friendly selection using inexpensive C/N sources to produce a high yield of PG together with chitinolytic and proteolytic enzymes by S. marcescens. The review article will provide effective references for production, bioactivity, and application of S. marcescens PG in various fields such as biocontrol agents and potential pharmaceutical drugs.

Microbial Reclamation of Chitin and Protein-Containing Marine By-Products for the Production of Prodigiosin and the Evaluation of Its Bioactivities

Chitin and protein-containing marine by-products (CPCMBPs), including crab shells, squid pens, and shrimp shells, were investigated as the sole carbon/nitrogen (C/N) source for prodigiosin (PG) production by Serratia marcescens TNU01 in a 250 mL Erlenmeyer flask and a 10 L bioreactor system. Among the used C/N source of CPCMBPs, squid pens powder (SPP) showed the most optimum PG productivity. Different ratios of chitin/protein combination were also used as the C/N sources for PG production. With a similar chitin/protein ratio (4/6) of squid pens, a significant PG productivity was achieved when the chitin/protein ratios were controlled in the range of 3/7-4/6. Maximum PG yield (3450 mg/L) by S. marcescens TNU01 was achieved in the bioreactor system containing 3 L medium of 1.75% SPP, 0.03% K₂HPO₄, and 0.05% MgSO₄ at 25 °C for 12 h in dark. The results of in vitro bioassays reveal that the purified PG possesses acetylcholinesterase inhibitory activity and antioxidant as well as anticancer activities. This study suggests that squid pens may have the potential to be used for cost effective production of bioactive PG at a large-scale.

Coagulation of Chitin Production Wastewater from Shrimp Scraps with By-Product Chitosan and Chemical Coagulants

Chitin production wastewater contains nutrient-rich organic and mineral contents. Coagulation of the wastewater with a natural coagulant such as by-product chitosan would be an economical and environmentally friendly method of treatment. This study investigated the treatment efficiencies of a preliminary sedimentation process followed by coagulation. The removal efficiencies for wastewater parameters were evaluated and compared for coagulants including by-product chitosan, polyaluminum chloride, and polyacryamide. The evaluation was based on the removal of wastewater turbidity and other criteria, including tCOD, sCOD, TKN, NH4+-N, TP, TSS, calcium, and crude protein. The results showed that the preliminary sedimentation (before coagulation) can remove over 80% of turbidity and more than 93% of TSS at pH 4 in 30 min. At optimal conditions, when the ratio of crude protein and calcium was 4.95, by-product chitosan dose of 77.5 mg·L-1 and pH = 8.3, the wastewater characteristics changes were tCOD 23%, sCOD 32%, TKN and ammonium 25%, TP 90%, TSS 84%, Ca2+ 29%, and crude protein 25%. The residue recovered through coagulation consists of up to 55 mg·g-1 crude protein, which is used for animal feed or crop fertilizer.

Erigeron annuus Protects PC12 Neuronal Cells from Oxidative Stress Induced by ROS-Mediated Apoptosis

Reactive oxygen species (ROS), associated with oxidative stress, are involved in many biological processes such as apoptosis, necrosis, and autophagy. Oxidative stress might induce neuronal damage via ROS generation, causing neurodegenerative diseases. Erigeron annuus (EA) has antioxidant properties and could protect neurons from oxidative stress. In this study, we investigated the protective effect of the aerial parts (EAA) and flowers (EAF) from EA on ROS-mediated apoptosis in pheochromocytoma 12 cells. We quantified 18 types of phenolic compounds using high-performance liquid chromatography. Pretreatment of the cells with EAA and EAF attenuated ROS generation and induced the expression of antioxidant enzymes such as superoxide dismutase 2, catalase, and glutathione peroxidase. In addition, EAF reduced the expression of apoptotic proteins such as Bax/Bcl-xL, caspase-3, and caspase-8 to a greater extent than that with EAA. These results suggested that the protective effect of EAF against oxidative stress-induced apoptosis might be due to the prevention of ROS generation mediated by oxidative enzymes.

Conversion of Shrimp Head Waste for Production of a Thermotolerant, Detergent-Stable, Alkaline Protease by Paenibacillus sp

Fishery processing by-products have been of great interest to researchers due to their beneficial applications in many fields. In this study, five types of marine by-products, including demineralized crab shell, demineralized shrimp shell, shrimp head, shrimp shell, and squid pen, provided sources of carbon and nitrogen nutrition by producing a protease from Paenibacillus sp. TKU047. Strain TKU047 demonstrated the highest protease productivity (2.98 U/mL) when cultured for two days on a medium containing 0.5% of shrimp head powder (SHP). The mass of TKU047 protease was determined to be 32 kDa (approximately). TKU047 protease displayed optimal activity at 70–80 °C and pH 9, with a pH range of stability from 6 to 11. TKU047 protease also showed stability in solutions containing surfactants and detergents. Based on its excellent properties, Paenibacillus sp. TKU047 protease may be a feasible candidate for inclusion in laundry detergents.

Genus Miliusa: A Review of Phytochemistry and Pharmacology

Background

Genus Miliusa (family Annonaceae), widely distributed in mainland Asia and Australia to New Guinea, has been employed in both traditional herbal uses and pharmacological medicines. Original research articles related to this genus are now available, but supportive reviews highlighting phytochemical and pharmacological aspects are now insufficient.

Objective

This account is an overview of most of the compounds isolated from this genus, along with their pharmacological evaluations.

Conclusion

A vast amount of data showed that genus Miliusa contained various classes of secondary metabolites. Herein, more than two hundred constituents were isolated, comprising alkaloids, geranylated homogentisic acids, flavonoids, lignans, neolignans, terpenoids, acetogenins, styryls, lactones, phenolics, amides, alcohols, and furfural derivatives. Novel miliusanes and bicyclic lactones have been remarkable characteristics of Miliusa plants. Essential oils from these plants were also detected, with a high amount of β-caryophyllene. Numerous in vitro biological researches on, for example, anticancer, antifungal, antimycobacterial, anti-inflammation, and cardiac activity, especially in terms of cytotoxicity, using either isolated compounds or plant extracts, implied that Miliusa phytochemical components now set out to have a key role in pharmacological development. M. smithiae ethyl acetate extract and its flavonoid ayanin (75) inhibited the growth of MCF-7 cell line comparable with positive control ellipticine. (+)-Miliusol (72) stimulated in vivo anticancer experiment against HCT116 xenograft mouse tumor following the p21-dependent induction of cellular senescence mechanism.

Reclamation of Fishery Processing Waste: A Mini-Review

: Seafood such as fish, shellfish, and squid are a unique source of nutrients. However, many marine processing byproducts, such as viscera, shells, heads, and bones, are discarded, even though they are rich sources of structurally diverse bioactive nitrogenous components. Based on emerging evidence of their potential health benefits, these components show significant promise as functional food ingredients. Fish waste components contain significant levels of high-quality protein, which represents a source for biofunctional peptide mining. The chitin contained in shrimp shells, crab shells, and squid pens may also be of value. The components produced by bioconversion are reported to have antioxidative, antimicrobial, anticancer, antihypertensive, antidiabetic, and anticoagulant activities. This review provides an overview of the extraordinary potential of processing fish and chitin-containing seafood byproducts via chemical procedures, enzymatic and fermentation technologies, and chemical modifications, as well as their applications.

Bioactivity-Guided Purification of Novel Herbal Antioxidant and Anti-NO Compounds from Euonymus laxiflorus Champ

Euonymus laxiflorus Champ., a medicinal herb collected in Vietnam, has been reported to show several potent bioactivities, including anti-NO, enzyme inhibition, hypoglycemic and antidiabetic effects. Recently, the antioxidant activity of Euonymus laxiflorus Champ. trunk bark (ELCTB) has also been reported. However, the active antioxidant and anti-NO constituents existing in ELCTB have not been reported in the literature. The objective of this study was to purify the active antioxidants from ELCTB and investigate the anti-NO effect of the major constituents. Twenty-two phenolics isolated from ELCTB, including 12 compounds newly isolated in this study (1–12) and 10 constituents obtained from our previous work, were evaluated for their antioxidant activity. Of these, 12 compounds (4–6, 9, 13–15, 18–22) showed a potent antioxidant capacity (FRS50 = 7.8–58.11 µg/mL), in comparison to α-tocopherol (FRS50 = 23 µg/mL). In the anti-NO activity tests, Walterolactone A (1a) and B (1b) β-d-glucopyranoside (13) demonstrated the most effective and comparable activity to that of quercetin with max inhibition and IC₅₀ values of 100%, 1.3 µg/mL, and 100%, 1.21 µg/mL, respectively. The crude extract and its major compounds showed no cytotoxicity on normal cells. Notably, three constituents (9, 11, and 12) were identified as new compounds, another three constituents, including 1, 7, and 8, were found to be new natural products, constituents 9 and 13 were determined to be new antioxidants, and compound 13 was reported to have novel potent anti-NO activity for the first time. The results of this study contribute to the enrichment of new natural products and compounds, as well as the novel biological activity of constituents isolated from Euonymus laxiflorus Champ. The current study also indicates ELCTB as a rich natural source of active phenolics. It is suggested that ELCTB could be developed as a health food with promising antioxidant and anti-NO effects, as well as other beneficial biological activities.

Reclamation of Marine Chitinous Materials for Chitosanase Production via Microbial Conversion by Paenibacillus macerans

Chitinous materials from marine byproducts elicit great interest among biotechnologists for their potential biomedical or agricultural applications. In this study, four kinds of marine chitinous materials (squid pens, shrimp heads, demineralized shrimp shells, and demineralized crab shells) were used to screen the best source for producing chitosanase by Paenibacillus macerans TKU029. Among them, the chitosanase activity was found to be highest in the culture using the medium containing squid pens as the sole carbon/nitrogen (C/N) source. A chitosanase which showed molecular weights at 63 kDa was isolated from P. macerans cultured on a squid pens medium. The purified TKU029 chitosanase exhibited optimum activity at 60 °C and pH 7, and was stable at temperatures under 50 °C and pH 3-8. An analysis by MALDI-TOF MS revealed that the chitosan oligosaccharides (COS) obtained from the hydrolysis of water-soluble chitosan by TKU029 crude enzyme showed various degrees of polymerization (DP), varying from 3⁻6. The obtained COS enhanced the growth of four lactic acid bacteria strains but exhibited no effect on the growth of E. coli. By specialized growth enhancing effects, the COS produced from hydrolyzing water soluble chitosan with TKU029 chitinolytic enzymes could have potential for use in medicine or nutraceuticals.

Production and Bioactivity-Guided Isolation of Antioxidants with α-Glucosidase Inhibitory and Anti-NO Properties from Marine Chitinous Materials

Natural and bioactive products have been of great interest due to their benefit as health foods and drugs to prevent various diseases. The aim of this study is to efficiently reuse marine chitinous materials (CMs), abundant and low-cost fishery by-products, for the bio-synthesis, isolation, and identification of antioxidant compounds possessing some other beneficial bioactivities. Paenibacillus sp. was used to convert CMs to antioxidants. Among various tested CMs, squid pen powder (SPP) gave the best results when used as the sole carbon/nitrogen source. Fermented SPP (FSPP) had comparable antioxidant activity (IC50 = 124 µg/mL) to that of α-tocopherol (IC50 = 30 µg/mL). The antioxidant productivity increased 1.83-fold after culture optimization. The use of multiple techniques, including Diaion, silica, and preparative HPLC columns coupled with a bioassay resulted in the isolation of two major antioxidants characterized as exopolysaccharides and homogentisic acid. These isolated compounds showed great maximum activity and low IC50 values (96%, 30 µg/mL and 99%, 5.4 µg/mL, respectively) which were comparable to that of α-tocopherol (95%, 24 µg/mL). The crude sample, fractions, and isolated compounds also demonstrated α-glucosidase inhibition and anti⁻inflammatory activity. Notably, homogentisic acid was found as a non-sugar-based moiety α-glucosidase inhibitor which show much higher inhibition (IC50 = 215 µg/mL) than that of acarbose (IC50 = 1324 µg/mL) and also possessed acceptable anti⁻inflammatory activity (IC50 = 9.8 µg/mL). The results highlighted the value of using seafood processing by-products, like squid pens, for the production of several compounds possessing multi-benefit bioactivities and no cytotoxicity.

Conversion of Squid Pens to Chitosanases and Proteases via Paenibacillus sp. TKU042

Chitosanases and proteases have received much attention due to their wide range of applications. Four kinds of chitinous materials, squid pens, shrimp heads, demineralized shrimp shells and demineralized crab shells, were used as the sole carbon and nitrogen (C/N) source to produce chitosanases, proteases and α-glucosidase inhibitors (αGI) by four different strains of Paenibacillus. Chitosanase productivity was highest in the culture supernatants using squid pens as the sole C/N source. The maximum chitosanase activity of fermented squid pens (0.759 U/mL) was compared to that of fermented shrimp heads (0.397 U/mL), demineralized shrimp shells (0.201 U/mL) and demineralized crab shells (0.216 U/mL). A squid pen concentration of 0.5% was suitable for chitosanase, protease and αGI production via Paenibacillus sp. TKU042. Multi-purification, including ethanol precipitation and column chromatography of Macro-Prep High S as well as Macro-Prep DEAE (diethylaminoethyl), led to the isolation of Paenibacillus sp. TKU042 chitosanase and protease with molecular weights of 70 and 35 kDa, respectively. For comparison, 16 chitinolytic bacteria, including strains of Paenibacillus, were investigated for the production of chitinase, exochitinase, chitosanase, protease and αGI using two kinds of chitinous sources.

Reclamation of Marine Chitinous Materials for the Production of α-Glucosidase Inhibitors via Microbial Conversion

Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N) sources for producing α-glucosidase inhibitors (aGI) by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP) and demineralized shrimp shell powder (deSSP) as the C/N source. The half maximal inhibitory concentration (IC₅₀) and maximum aGI activity of fermented deCSP (38 µg/mL, 98%), deSSP (108 µg/mL, 89%), squid pen powder (SPP) (422 µg/mL, 98%), and shrimp head powder (SHP) (455 µg/mL, 92%) were compared with those of fermented nutrient broth (FNB) (81 µg/mL, 93%) and acarbose (1095 µg/mL, 74%), a commercial antidiabetic drug. The result of the protein/chitin ratio on aGI production showed that the optimal ratio was 0.2/1. Fermented deCSP showed lower IC₅₀ and higher maximum inhibitory activity than those of acarbose against rat intestinal α-glucosidase.

Utilization of Fishery Processing By-Product Squid Pens for α-Glucosidase Inhibitors Production by Paenibacillus sp

The supernatants (the solution part received after centrifugation) of squid pens fermented by four species of Paenibacillus showed potent inhibitory activity against α-glucosidases derived from yeast (79–98%) and rats (76–83%). The inhibition of acarbose—a commercial antidiabetic drug, used against yeast and rat α-glucosidases—was tested for comparison; it showed inhibitory activity of 64% and 88%, respectively. Other chitinolytic or proteolytic enzyme-producing bacterial strains were also used to ferment squid pens, but no inhibition activity was detected from the supernatants. Paenibacillus sp. TKU042, the most active α-glucosidase inhibitor (aGI)-producing strain, was selected to determine the optimal cultivation parameters. This bacterium achieved the highest aGI productivity (527 µg/mL) when 1% squid pens were used as the sole carbon/nitrogen source with a medium volume of 130 mL (initial pH 6.85) in a 250 mL flask (48% of air head space), at 30 °C for 3–4 d. The aGI productivity increased 3.1-fold after optimization of the culture conditions. Some valuable characteristics of Paenibacillus aGIs were also studied, including pH and thermal stability and specific inhibitory activity. These microbial aGIs showed efficient inhibition against α-glucosidases from rat, yeast, and bacteria, but weak inhibition against rice α-glucosidase with IC₅₀ values of 362, 252, 189, and 773 µg/mL, respectively. In particular, these aGIs showed highly stable activity over a large pH (2–13) and temperature range (40–100 °C). Various techniques, including: Diaoin, Octadecylsilane opened columns, and preparative HPLC coupled with testing bioactivity resulted in isolating a main active compound; this major inhibitor was identified as homogentisic acid (HGA). Notably, HGA was confirmed as a new inhibitor, a non-sugar-based aGI, and as possessing stronger activity than acarbose with IC_50, and maximum inhibition values of 220 μg/mL, 95%, and 1510 μg/mL, 65%, respectively. These results suggest that squid pens, an abundant and low-cost fishery processing by-product, constitute a viable source for the production of antidiabetic materials via fermentation by strains of Paenibacillus. This fermented product shows promising applications in diabetes or diabetes related to obesity treatment due to their stability, potent bioactivity, and efficient inhibition against mammalian enzymes.

Biosynthesis of α-Glucosidase Inhibitors by a Newly Isolated Bacterium, Paenibacillus sp. TKU042 and Its Effect on Reducing Plasma Glucose in a Mouse Model

Paenibacillus sp. TKU042, a bacterium isolated from Taiwanese soil, produced α-glucosidase inhibitors (aGIs) in the culture supernatant when commercial nutrient broth (NB) was used as the medium for fermentation. The supernatant of fermented NB (FNB) showed stronger inhibitory activities than acarbose, a commercial anti-diabetic drug. The IC50 and maximum α-glucosidase inhibitory activities (aGIA) of FNB and acarbose against α-glucosidase were 81 μg/mL, 92% and 1395 μg/mL, 63%, respectively. FNB was found to be strongly thermostable, retaining 95% of its relative activity, even after heating at 100 °C for 30 min. FNB was also stable at various pH values. Furthermore, FNB demonstrated antioxidant activity (IC50 = 2.23 mg/mL). In animal tests, FNB showed remarkable reductions in the plasma glucose of ICR (Institute of Cancer Research) mice at a concentration of 200 mg/kg. Combining FNB and acarbose enhanced the effect even more, with an added advantage of eliminating diarrhea. According to HPLC (High-performance liquid chromatography) fingerprinting, the Paenibacillus sp. TKU042 aGIs were not acarbose. All of the results suggest that Paenibacillus sp. TKU042 FNB could have potential use as a health food or to treat type 2 diabetes.