Cytotoxic phenazine and antiallergic phenoxazine alkaloids from an arctic Nocardiopsis dassonvillei SCSIO 502F.

Microbes well-adapted to the Arctic Ocean are promising for producing novel compounds, due to their fancy strategies for adaptation and being under-investigated. Two new phenazine alkaloids (1 and 2) and one new phenoxazine (3) were isolated from Nocardiopsis dassonvillei 502F, a strain originally isolated from Arctic deep-sea sediments. AntiSMASH analysis of the genome of Nocardiopsis dassonvillei 502F revealed the presence of 16 putative biosynthetic gene clusters (BGCs), including a phenazine BGC. Most of the isolated compounds were evaluated for their antibacterial, antiallergic, and cytotoxic activities. Among them, compounds 4 and 5 exhibited potent in vitro cytotoxic activities against osteosarcoma cell line 143B with IC50 values 0.16 and 20.0 µM, respectively. Besides, the results of antiallergic activities of compounds 6-8 exhibited inhibitory activities with IC50 values of 10.88 ± 3.05, 38.88 ± 3.29, and 2.44 ± 0.17 µg/mL, respectively (IC50 91.6 µM for the positive control loratadine).

Bisabolane-type sesquiterpenoids and bacillibactin from the marine-derived fungus Aspergillus sydowii SCSIO 41041 and their enzyme inhibiting activity.

Twelve compounds, including eleven bisabolane-type sesquiterpenoids (1 - 11), and one bacillibactin (12) were identified from marine-derived fungus Aspergillus sydowii SCSIO 41041 isolated from Creseis acicula. The chemical structures were elucidated by the basis of spectroscopic evidences, including HRESIMS, NMR and optical rotation. Biologically, all compounds were evaluated for their acetyl cholin-esterase (AChE) enzyme, pancreatic lipase (PL) enzyme, neuraminidase (NA) and phosphodiesterase 4 (PDE4) inhibitory activities. Compound 12 displayed significant inhibitory activity against neuraminidase (NA) with an IC50 value of 24.0 µM, which was equivalent to the positive drug oseltamivir phosphate (IC50 value of 20.0 µM). And the NA inhibitory activity was confirmed by molecular docking analysis.

Indole diketopiperazine alkaloids and aromatic polyketides from the Antarctic fungus Penicillium sp. SCSIO 05705.

A new indole diketopiperazine alkaloid, named penilline D (1), together with five known indole alkaloid analogues (2-5, 11), two meroterpenoids (6 and 12), and four butenolide derivatives (7-10), were isolated from the Antarctic fungus Penicillium sp. SCSIO 05705. Extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation were used to elucidate the structure of penilline D (1), including its absolute configuration. All isolated compounds (1-12) were evaluated for their cytotoxic, antibacterial and enzyme inhibitory activities against acetylcholinesterase (AChE) and pancreatic lipase (PL). Among them, compound 5 exhibited moderate in vitro cytotoxic activity against the 143B cell line with IC50 value of 12.64 ± 0.78 µM. Compound 6 showed strong inhibitory activity against AChE with IC50 value of 0.36 nM (IC50 18.7 nM for Tacrine), while compounds 6 and 11 showed weak PL enzyme inhibitory activity. Furthermore, an in silico molecular docking study was also performed between 6 and AChE.

One new furanone analogue from the deep-sea fungus Purpureocillium sp. SCSIO 06693.

A new furanone analog, (E)-2-(8,9-dihydroxy-6,8-dimethyldec-4-en-2-yl)-met-hylfuran-3(2H)-one (1), together with six known compounds, including two diterpenoids (2 and 3), one butyrolactone (4) and three isocoumarins (5-7), were isolated from a deep-sea fungus, Purpureocillium sp. SCSIO 06693. Among them, compound 1 existed as two tautomeric forms (1a and 1b) differing in configuration of the furan ring. The chemical structures were elucidated by the basis of spectroscopic evidences, including HRESIMS, NMR and optical rotation. Isolated compounds were evaluated for their cytotoxic, antiviral, antibacterial, antioxidant, acetyl cholinesterase (AChE) and pancreatic lipase (PL) enzyme inhibitory activities. Biological evaluation results revealed that compound 4 showed modest antioxidant activity against DPPH with IC50 value of 72.03 µM. In addition, compounds 1-4 exhibited PL enzyme inhibitory activities.

Citrinin and α-pyrone derivatives with pancreatic lipase inhibitory activities from Penicillium sp. SCSIO 41302.

One new citrinin monomer derivative (1), and two new natural products α-pyrone analogues (2a and 2b), were isolated from the sponge derived fungus Penicillium sp. SCSIO 41302. Their structures were determined by extensive spectroscopic analysis, chiral-phase HPLC analysis, modified Mosher's method, ECD calculations, and X-ray single-crystal diffraction. Bioactivity screening showed that compounds 2b and 8 exhibited obvious inhibitory activities against pancreatic lipase and acetyl cholinesterase with IC50 values of 48.5 and 4.8 µM, respectively, which indicated that different chiral center between enantiomers (2a and 2b) might result in different biological activities (IC50 value against PL for 2a >100 µg/ml).

Pyrrolyl 4-quinolone alkaloids from the mangrove endophytic fungus Penicillium steckii SCSIO 41025: Chiral resolution, configurational assignment, and enzyme inhibitory activities.

Six undescribed 4-quinolone alkaloids, including four racemic mixtures, (±)-oxypenicinolines A-D, and two related ones, penicinolines F and G, together with seven known analogues, were isolated from the mangrove-derived fungus Penicillium steckii SCSIO 41025 (Trichocomaceae). The racemates were separated by HPLC using chiral columns. Their structures including absolute configurations were elucidated by extensive spectroscopic analysis, electronic circular dichroism (ECD) experiments, and single-crystal X-ray diffraction analysis. Structurally, (±)-oxypenicinolines A-D shared with an unusual 6/6/5/5 tetracyclic system incorporating a rare tetrahydro-pyrrolyl moiety. A plausible biosynthetic pathway for pyrrolyl 4-quinolone alkaloids is proposed. (±)-oxypenicinoline A and quinolactacide displayed α-glucosidase inhibitory activity with the IC50 values of 317.8 and 365.9 µΜ, respectively, which were more potent than that of acarbose (461.0 µM). Additionally, penicinoline and penicinoline E showed weak inhibitions toward acetylcholinesterase (AChE).

The marine-derived furanone reduces intracellular lipid accumulation in vitro by targeting LXRα and PPARα.

Recent studies have demonstrated that commercially available lipid-lowering drugs cause various side effects; therefore, searching for anti-hyperlipidaemic compounds with lower toxicity is a research hotspot. This study was designed to investigate whether the marine-derived compound, 5-hydroxy-3-methoxy-5-methyl-4-butylfuran-2(5H)-one, has an anti-hyperlipidaemic activity, and the potential underlying mechanism in vitro. Results showed that the furanone had weaker cytotoxicity compared to positive control drugs. In RAW 264.7 cells, the furanone significantly lowered ox-LDL-induced lipid accumulation (~50%), and its triglyceride (TG)-lowering effect was greater than that of liver X receptor (LXR) agonist T0901317. In addition, it significantly elevated the protein levels of peroxisome proliferator-activated receptors (PPARα) and ATP-binding cassette (ABC) transporters, which could be partially inhibited by LXR antagonists, GSK2033 and SR9243. In HepG2 cells, it significantly decreased oleic acid-induced lipid accumulation, enhanced the protein levels of low-density lipoprotein receptor (LDLR), ABCG5, ABCG8 and PPARα, and reduced the expression of sterol regulatory element-binding protein 2 (~32%). PPARα antagonists, GW6471 and MK886, could significantly inhibit the furanone-induced lipid-lowering effect. Furthermore, the furanone showed a significantly lower activity on the activation of the expression of lipogenic genes compared to T0901317. Taken together, the furanone exhibited a weak cytotoxicity but had powerful TC- and TG-lowering effects most likely through targeting LXRα and PPARα, respectively. These findings indicate that the furanone has a potential application for the treatment of dyslipidaemia.

Nimesulide increases the aldehyde oxidase activity of humans and rats.

An increasing number of drugs are metabolized by aldehyde oxidase (AOX), but AOX-mediated drug interactions are seldom reported due to the lack of appropriate inhibitors and inducers. A recent study reported that nimesulide (NIM) could increase the liver injury risk of methotrexate. The latter was mainly metabolized by AOX to form hepatotoxic 7-hydroxymethotrexate (7-OH MTX). Thus, we speculated that NIM could induce AOX. In this study, we investigated the potential induction of AOX activity by NIM using methotrexate as the probe substrate. Treatment of primary human and rat hepatocytes with NIM (20 µM) for 24 h caused a 2.0- and 3.1-fold, respectively, increase in 7-OH MTX formation. Oral administration of NIM (100 mg·kg-1·d-1, for 5 days) to rats significantly increased the systematic exposure (6.5-fold), liver distribution (2.5-fold), and excretion (5.2-fold for urinary excretion and 2.1-fold for fecal excretion) of 7-OH MTX. The 7-OH MTX formation in liver cytosol from rats pretreated with 20, 50, and 100 mg·kg-1·d-1 NIM for 5 days increased by 1.9-, 3.2-, and 3.7-fold, respectively, compared with that of rats pretreated with the vehicle. We revealed that the elevation of AOX activity was accompanied by an increase in AOX1 protein levels but not the corresponding mRNA levels. Collectively, our results demonstrate for the first time that NIM can increase the AOX activity of humans and rats, and may raise concerns regarding the risk of drug interactions between NIM and AOX substrates in clinical practice.

Hexagonal Boron Nitride/Microfibril Cellulose/Poly(vinyl alcohol) Ternary Composite Film with Thermal Conductivity and Flexibility.

Microfibril cellulose (MFC), which is detrimental to soil cultivation and environmental protection, is derived from waste pineapple leaves. Hexagonal boron nitride (h-BN) was modified with polydopamine (PDA)-PDA@h-BN named pBN, and then combined with MFC to prepare a novel hybrid powder. The effect of PDA on h-BN and the binding effect between pBN and MFC were characterized by X-ray photoelectron spectroscopy (XPS), Thermogravimetric (TG), scanning electron microscopy (SEM), and Fourier Transform-Infrared (FT-IR). Poly (vinyl alcohol) (PVA) was used as an eco-friendly polymeric matrix to prepare a pBN-MFC-PVA composite film. The mechanical strength, hydrophobicity, and thermal conductivity of the film were studied and the results confirmed that h-BN was chemically modified with PDA and was uniformly distributed along the MFC. The thermal conductivity of the pBN-MFC-PVA composite film increased with the addition of a pBN-MFC novel powder. MFC acted as "guides" to mitigate the h-BN agglomerate. In addition to the possible usage in the pBN-MFC-PVA composite film itself, the pBN-MFC hybrid powder may be a potential filler candidate for manufacturing thermal interface materials and wearable devices or protective materials.

Retinol saturase modulates lipid metabolism and the production of reactive oxygen species.

Retinol saturase (RetSat) catalyzes the saturation of double bonds of all-trans-retinol leading to the production of dihydroretinoid metabolites. Beside its role in retinoid metabolism, there is evidence that RetSat modulates the cellular response to oxidative stress and plays critical roles in adipogenesis and the accumulation of lipids. Here, we explore the relationship between RetSat, lipid metabolism and oxidative stress using in vitro and in vivo models with altered expression of RetSat. Our results reveal that RetSat is a potent modulator of the cellular response to oxidative stress and the generation of reactive oxygen species (ROS). The levels of reactive aldehydes products of lipid peroxidation, as measured based on thiobarbituric acid reactivity, are increased in RetSat overexpressing cells and, conversely, reduced in cells and tissues with reduced or absent expression of RetSat compared to controls. Despite increased weight gain, neutral lipid accumulation and alterations in hepatic lipid composition, RetSat-/- mice exhibit normal responses to insulin. In conclusion, our findings further expand upon the role of RetSat in oxidative stress and lipid metabolism and could provide insight in the significance of alterations of RetSat expression as observed in metabolic disorders.

Sesquiterpenes from the whole plants of Parasenecio roborowskii.

Six eremophilane-type (parasenolide A-F) and an eudesmane-type (parasenin) sesquiterpenoids, along with eight known sesquiterpenes, were isolated from the whole plants of Parasenecio roborowskii. The structures and absolute configurations of new compounds were elucidated using extensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR experiments, the CD exciton chirality methods, and single-crystal X-ray crystallography. All isolated compounds were evaluated for cytotoxicity against five human cancer (HeLa, HepG2, K562, MDA231, and NCI-H460) cell lines and a murine melanoma B16 F10 cell line by MTT assay. Compounds 1-15 showed cytotoxic activities, especially compounds 3, 4, 8, 10, and 12. These five compounds showed broad spectrum activities against all the tested cancer cell lines with IC50 ranging from 9.2 to 35.5µM. The study supports that eremophilenolides and eudesmane-type sesquiterpenes occur mainly in the genus Parasenecio and can be used as a chemosystematic marker of the genus.

Sex differences in colonization of gut microbiota from a man with short-term vegetarian and inulin-supplemented diet in germ-free mice.

Gnotobiotic mouse model is generally used to evaluate the efficacy of gut microbiota. Sex differences of gut microbiota are acknowledged, yet the effect of recipient's gender on the bacterial colonization remains unclear. Here we inoculated male and female germ-free C57BL/6J mice with fecal bacteria from a man with short-term vegetarian and inulin-supplemented diet. We sequenced bacterial 16S rRNA genes V3-V4 region from donor's feces and recipient's colonic content. Shannon diversity index showed female recipients have higher bacteria diversity than males. Weighted UniFrac principal coordinates analysis revealed the overall structures of male recipient's gut microbiota were significantly separated from those of females, and closer to the donor. Redundancy analysis identified 46 operational taxonomic units (OTUs) differed between the sexes. The relative abundance of 13 OTUs were higher in males, such as Parabacteroides distasonis and Blautia faecis, while 33 OTUs were overrepresented in females, including Clostridium groups and Escherichia fergusonii/Shigella sonnei. Moreover, the interactions of these differential OTUs were sexually distinct. These findings demonstrated that the intestine of male and female mice preferred to accommodate microbiota differently. Therefore, it is necessary to designate the gender of gnotobiotic mice for complete evaluation of modulatory effects of gut microbiota from human feces upon diseases.

Quinones and coumarins from Ajania salicifolia and their radical scavenging and cytotoxic activity.

1,4-Naphthoquinone (1) and a new coumarin (3) were isolated from Ajania salicifolia, together with two known compounds (2, 4). The structures and stereochemistry of new compounds were elucidated using spectroscopic methods. Two compounds exhibited potent ABTS cation radical scavenging activities with IC50 values ranging 7.97-8.44 µM. Two quinones (1, 2) exhibited moderate cytotoxic activity against the human cancer cell lines (Hela, HepG2, and K562) with IC50 values of 11.24-35.15 µM in vitro. This is the first report of naphthoquinone in the genus Ajania.

PEComa of the uterus with coexistence of situs inversus totalis, a case report and literature review.

PEComas are a group of very rare mesenchymal neoplasms, which express myogenic and melanocytic markers, such as HMB-45 and actin. Situs inversus totalis represents a complete left to right side transposition of the asymmetrical thoracic and abdominal organs and incorporates dextrocardia. The presence of uterus PEComa in the setting of situs inversus totalis is extremely rare. Here, we report a case of PEComa of uterus with coexistence of situs inversus totalis and review the literatures. To the best of our knowledge this is the fist report of a uterus PEComa patient with situs inversus totalis.

Unfolded protein response mediated JNK/AP-1 signal transduction, a target for ovarian cancer treatment.

Researches have revealed several stressors, which could activate unfolded protein response (UPR) in cells. However, the survival or death pathway was determined by the duration of UPR exposure. Based on the UPR mediated death pathway, our study was aimed to investigate role of UPR on c-Jun N-terminal kinase (JNK)/activator protein-1 (Ap-1) signal transduction in diindolylmethane (DIM) treated ovarian cancer cell lines. Activation of UPR proteins, UPR mediated apoptotic signaling proteins and expression level of EpCAM, JNK, Ap-1, Caspase-3 and Bcl-2 were measured. Protein and gene expression, transcription factor activity, and protein phosphorylation were measured using standard molecular biology techniques. Our results demonstrated DIM treatment had significantly increased the expression of Endoplasmic reticulum (ER) stress regulators such as Bip, IRE1, CHOP and activation of UPR related apoptotic proteins in ovarian cancer cells. Decreased expression of EpCAM and activity of AP-1 transcription factor were observed in DIM treated cells. The pharmacologic inhibitors of the JNK signal transduction pathway, suggest that the impact of EpCAM expression on AP-1 transcription factor activity is mediated through the JNK pathway. Taken together, these results suggest that UPR mediated JNK/Ap-1 signal transduction has a significant role in the regulation of apoptosis in human ovarian cancer cells, and is a potential molecular target to enhance sensitivity of ovarian cancer to chemotherapy.

Metabolic markers and microecological characteristics of tongue coating in patients with chronic gastritis.

BACKGROUND: In Traditional Chinese Medicine (TCM), tongue diagnosis has been an important diagnostic method for the last 3000 years. Tongue diagnosis is a non-invasive, simple and valuable diagnostic tool. TCM treats the tongue coating on a very sensitive scale that reflects physiological and pathological changes in the organs, especially the spleen and stomach. Tongue coating can diagnose disease severity and determine the TCM syndrome ("Zheng" in Chinese). The biological bases of different tongue coating appearances are still poorly understood and lack systematic investigation at the molecular level. METHODS: Tongue coating samples were collected from 70 chronic gastritis patients and 20 normal controls. 16S rRNA denatured gradient gel electrophoresis (16S rRNA-DGGE) and liquid chromatography and mass spectrometry (LC-MS) were designed to profile tongue coatings. The statistical techniques used were principal component analysis and partial least squares-discriminate analysis. RESULTS: Ten potential metabolites or markers were found in chronic gastritis patients, including UDP-D-galactose, 3-ketolactose, and vitamin D2, based on LC-MS. Eight significantly different strips were observed in samples from chronic gastritis patients based on 16S rRNA-DGGE. Two strips, Strips 8 and 10, were selected for gene sequencing. Strip 10 sequencing showed a 100% similarity to Rothia mucilaginosa. Strip 8 sequencing showed a 96.2% similarity to Moraxella catarrhalis. CONCLUSIONS: Changes in glucose metabolism could possibly form the basis of tongue coating conformation in chronic gastritis patients. The study revealed important connections between metabolic components, microecological components and tongue coating in chronic gastritis patients. Compared with other diagnostic regimens, such as blood tests or tissue biopsies, tongue coating is more amenable to, and more convenient for, both patients and doctors.

The retinaldehyde reductase DHRS3 is essential for preventing the formation of excess retinoic acid during embryonic development.

Oxidation of retinol via retinaldehyde results in the formation of the essential morphogen all-trans-retinoic acid (ATRA). Previous studies have identified critical roles in the regulation of embryonic ATRA levels for retinol, retinaldehyde, and ATRA-oxidizing enzymes; however, the contribution of retinaldehyde reductases to ATRA metabolism is not completely understood. Herein, we investigate the role of the retinaldehyde reductase Dhrs3 in embryonic retinoid metabolism using a Dhrs3-deficient mouse. Lack of DHRS3 leads to a 40% increase in the levels of ATRA and a 60% and 55% decrease in the levels of retinol and retinyl esters, respectively, in Dhrs3(-/-) embryos compared to wild-type littermates. Furthermore, accumulation of excess ATRA is accompanied by a compensatory 30-50% reduction in the expression of ATRA synthetic genes and a 120% increase in the expression of the ATRA catabolic enzyme Cyp26a1 in Dhrs3(-/-) embryos vs. controls. Excess ATRA also leads to alterations (40-80%) in the expression of several developmentally important ATRA target genes. Consequently, Dhrs3(-/-) embryos die late in gestation and display defects in cardiac outflow tract formation, atrial and ventricular septation, skeletal development, and palatogenesis. These data demonstrate that the reduction of retinaldehyde by DHRS3 is critical for preventing formation of excess ATRA during embryonic development.

Pharmacokinetics of ganoderic acid D and its main metabolite by liquid chromatography-tandem mass spectrometry.

The present study aims to investigate the pharmacokinetics of ganoderic acid D (GD), a representative active triterpenoid from Ganoderma lucidum. A sensitive and selective liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of the concentrations of GD and its main metabolite (ganoderic acid B) in rat plasma. Following protein precipitation, the analytes were separated on a reversed-phase C18 column. Acetonitrile-water-acetic acid (40:60:0.01) was used at a flow-rate of 0.2ml/min. A triple quadrupole mass spectrometer equipped with an electrospray ionization source was used as the detector and was operated in the negative ion mode. Multiple reaction monitoring using the characteristic transitions was performed to quantify the analytes. The method had a lower limit of quantification of 8.19ng/ml for GD, and 8.59ng/ml for ganoderic acid B (GB). The calibration curves were demonstrated to be linear over the concentration range of 8.19-4096ng/ml and 8.59-2149ng/ml, respectively. Variations within- and between-batch were less than 6.4% and 4.6%, respectively. The extraction recovery rates ranged from 98.8 to 105.2% and 100.7 to 113.6%, respectively. The validated method was successfully applied to the quantification of GD and GB concentrations in rat plasma after oral administration (or intravenous administration) of GD preparations at a dose of 15mg/kg. The data showed that the absolute bioavailability increased from 22% to 70% after the GD suspension was changed to GD loaded solid lipid nanoparticles. In the meantime, the Cmax increased from 107.2 to 1555.6ng/ml; the tmax changed from 2.0h to 0.3h. These results are very helpful in the further studies.

[The oral microbial fingerprint on the greasy tongue coating of patients with chronic gastritis].

OBJECTIVE: To investigate the microbial changes on the greasy tongue coating of the patients with chronic gastritis and to explore the formation mechanism of greasy tongue coating. METHODS: Forty cases of tongue coating samples from patients with chronic gastritis were collected, 20 cases of greasy fur (as the greasy fur group), 20 cases of non-greasy fur (as the non-greasy fur group), and 20 cases of tongue coating samples from healthy subjects (as the healthy control group). Using 16S rRNA gene denatured gradient gel electrophoresis (DGGE) the microbial population of the tongue coating was detected. The DGGE fingerprint of the bacterium on the tongue coating was obtained. After digitalized principle component analysis (PCA) and partial least squares (PLS-DA) were performed. RESULTS: The microorganism compositions are different in the greasy fur group, the non-greasy fur group, and the healthy control group. (1) There were five significantly different bands between the greasy fur group and the non-greasy fur group, with the accuracy of 97.5% in judging the model. There were 8 significantly different bands between the greasy fur group and the healthy control group, with the accuracy of 95.0% in judging the model. There was no obvious difference between the healthy control group and the non-greasy fur group. (2) The brightness of band 8 was higher in the greasy fur group than in the non-greasy fur group and the healthy control group. It may be a new species closely associated with the formation of greasy tongue coating. Results of the sequence showed its nearest neighbor was Moraxella catarrhalis, but with the similarity of 96.2%. The brightness of band 10 was sequenced as the healthy control group > the non-greasy fur group > the greasy fur group. Results of the sequence showed it had 100.0% similarity to Rothia mucilaginosa (stick-slip Ross strain). CONCLUSIONS: The bacteria species on band 8 may have a close correlation with the formation of greasy fur of chronic gastritis, while the bacteria species on band 10 may have a close correlation with the formation of non-greasy fur. They indicated the microbial changes in the oral cavity may be one of the formation mechanisms for greasy tongue coating.

Structure/function relationships of adipose phospholipase A2 containing a cys-his-his catalytic triad.

Adipose phospholipase A(2) (AdPLA or Group XVI PLA(2)) plays an important role in the onset of obesity by suppressing adipose tissue lipolysis. As a consequence, AdPLA-deficient mice are resistant to obesity induced by a high fat diet or leptin deficiency. It has been proposed that AdPLA mediates its antilipolytic effects by catalyzing the release of arachidonic acid. Based on sequence homology, AdPLA is part of a small family of acyltransferases and phospholipases related to lecithin:retinol acyltransferase (LRAT). To better understand the enzymatic mechanism of AdPLA and LRAT-related proteins, we solved the crystal structure of AdPLA. Our model indicates that AdPLA bears structural similarity to proteins from the NlpC/P60 family of cysteine proteases, having its secondary structure elements configured in a circular permutation of the classic papain fold. Using both structural and biochemical evidence, we demonstrate that the enzymatic activity of AdPLA is mediated by a distinctive Cys-His-His catalytic triad and that the C-terminal transmembrane domain of AdPLA is required for the interfacial catalysis. Analysis of the enzymatic activity of AdPLA toward synthetic and natural substrates indicates that AdPLA displays PLA(1) in addition to PLA(2) activity. Thus, our results provide insight into the enzymatic mechanism and biochemical properties of AdPLA and LRAT-related proteins and lead us to propose an alternate mechanism for AdPLA in promoting adipose tissue lipolysis that is not contingent on the release of arachidonic acid and that is compatible with its combined PLA(1)/A(2) activity.