Isolation of Caribbean Ciguatoxin-5 (C-CTX5) and confirmation of its structure by NMR spectroscopy.

Ciguatera poisoning occurs throughout subtropical and tropical regions globally. The Virgin Islands in the Caribbean Sea is a known hyperendemic region for ciguatera and has been associated with Caribbean ciguatoxin (C-CTX) contamination in fish. An algal C-CTX (C-CTX5) was identified in Gambierdiscus silvae and G. caribeaus isolated from benthic algal samples collected in waters south St. Thomas, US Virgin Islands. The highest CTX-producing isolate, G. silvae 1602 SH-6, was grown at large-scale to isolate sufficient C-CTX5 for structural confirmation by NMR spectroscopy. A series of orthogonal extraction and fractionation procedures resulted in purification of approximately 40 µg of C-CTX5, as estimated by quantitative NMR. A suite of 1D and 2D NMR experiments were acquired that verified the structure originally proposed for C-CTX5. The structural confirmation and successful isolation of C-CTX5 opens the way for work on the stability, toxicology and biotransformation of C-CTXs, as well as for the production of quantitative reference materials for analytical method development and validation. The strategies developed for purification of C-CTX5 may also apply to isolation and purification of CTXs from the Pacific Ocean and other regions.

Targeted Metabolite Fingerprints of Thirteen Gambierdiscus, Five Coolia and Two Fukuyoa Species.

The genus Gambierdiscus produces an array of bioactive hydrophilic and lipophilic secondary metabolites that range in mode of action and toxicity. In this study, the metabolite fingerprint was mapped for thirteen Gambierdiscus, five Coolia and two Fukuyoa species (34 isolates) by assessing the production of 56 characterised secondary metabolites. Gambierdiscus polynesiensis was the only species to produce Pacific-ciguatoxin-3B (P-CTX3B), P-CTX3C, iso-P-CTX3B/C, P-CTX4A, P-CTX4B and iso-P-CTX4A/B. G. australes produced maitotoxin-1 (MTX-1) and MTX-5, G. cheloniae produced MTX-6 and G. honu produced MTX-7. Ubiquitous production of 44-methylgambierone was observed amongst all the Gambierdiscus isolates, with nine species also producing gambierone. Additional gambierone analogues, including anhydrogambierone (tentatively described herein), were also detected in all Gambierdiscus species, two Coolia and two Fukuyoa species. Gambieroxide was detected in G. lewisii and G. pacificus and gambieric acid A was detected in ten Gambierdiscus species, with G. australes (CAWD381) being the only isolate to produce gambieric acids A-D. This study has demonstrated that the isolates tested to date produce the known CTXs or MTXs, but not both, and highlighted several species that produced 'unknown' compounds displaying characteristics of cyclic polyethers, which will be the focus of future compound discovery efforts.

Gambierone and Sodium Channel Specific Bioactivity Are Associated with the Extracellular Metabolite Pool of the Marine Dinoflagellate Coolia palmyrensis.

Tropical epibenthic dinoflagellate communities produce a plethora of bioactive secondary metabolites, including the toxins ciguatoxins (CTXs) and potentially gambierones, that can contaminate fishes, leading to ciguatera poisoning (CP) when consumed by humans. Many studies have assessed the cellular toxicity of causative dinoflagellate species to better understand the dynamics of CP outbreaks. However, few studies have explored extracellular toxin pools which may also enter the food web, including through alternative and unanticipated routes of exposure. Additionally, the extracellular exhibition of toxins would suggest an ecological function and may prove important to the ecology of the CP-associated dinoflagellate species. In this study, semi-purified extracts obtained from the media of a Coolia palmyrensis strain (DISL57) isolated from the U.S. Virgin Islands were assessed for bioactivity via a sodium channel specific mouse neuroblastoma cell viability assay and associated metabolites evaluated by targeted and non-targeted liquid chromatography tandem and high-resolution mass spectrometry. We found that extracts of C. palmyrensis media exhibit both veratrine enhancing bioactivity and non-specific bioactivity. LC-HR-MS analysis of the same extract fractions identified gambierone and multiple undescribed peaks with mass spectral characteristics suggestive of structural similarities to polyether compounds. These findings implicate C. palmyrensis as a potential contributor to CP and highlight extracellular toxin pools as a potentially significant source of toxins that may enter the food web through multiple exposure pathways.

Structural Characterization of Maitotoxins Produced by Toxic Gambierdiscus Species.

Identifying compounds responsible for the observed toxicity of the Gambierdiscus species is a critical step to ascertaining whether they contribute to ciguatera poisoning. Macroalgae samples were collected during research expeditions to Rarotonga (Cook Islands) and North Meyer Island (Kermadec Islands), from which two new Gambierdiscus species were characterized, G. cheloniae CAWD232 and G. honu CAWD242. Previous chemical and toxicological investigations of these species demonstrated that they did not produce the routinely monitored Pacific ciguatoxins nor maitotoxin-1 (MTX-1), yet were highly toxic to mice via intraperitoneal (i.p.) injection. Bioassay-guided fractionation of methanolic extracts, incorporating wet chemistry and chromatographic techniques, was used to isolate two new MTX analogs; MTX-6 from G. cheloniae CAWD232 and MTX-7 from G. honu CAWD242. Structural characterization of the new MTX analogs used a combination of analytical chemistry techniques, including LC-MS, LC-MS/MS, HR-MS, oxidative cleavage and reduction, and NMR spectroscopy. A substantial portion of the MTX-7 structure was elucidated, and (to a lesser extent) that of MTX-6. Key differences from MTX-1 included monosulfation, additional hydroxyl groups, an extra double bond, and in the case of MTX-7, an additional methyl group. To date, this is the most extensive structural characterization performed on an MTX analog since the complete structure of MTX-1 was published in 1993. MTX-7 was extremely toxic to mice via i.p. injection (LD50 of 0.235 µg/kg), although no toxicity was observed at the highest dose rate via oral administration (155.8 µg/kg). Future research is required to investigate the bioaccumulation and likely biotransformation of the MTX analogs in the marine food web.

LC-HRMS and Chemical Derivatization Strategies for the Structure Elucidation of Caribbean Ciguatoxins: Identification of C-CTX-3 and -4.

Ciguatera poisoning is linked to the ingestion of seafood that is contaminated with ciguatoxins (CTXs). The structural variability of these polyether toxins in nature remains poorly understood due to the low concentrations present even in highly toxic fish, which makes isolation and chemical characterization difficult. We studied the mass spectrometric fragmentation of Caribbean CTXs, i.e., the epimers C-CTX-1 and -2 (1 and 2), using a sensitive UHPLC-HRMS/MS approach in order to identify product ions of diagnostic value. We found that the fragmentation of the ladder-frame backbone follows a characteristic pattern and propose a generalized nomenclature for the ions formed. These data were applied to the structural characterization of a pair of so far poorly characterized isomers, C-CTX-3 and -4 (3 and 4), which we found to be reduced at C-56 relative to 1 and 2. Furthermore, we tested and applied reduction and oxidation reactions, monitored by LC-HRMS, in order to confirm the structures of 3 and 4. Reduction of 1 and 2 with NaBH4 afforded 3 and 4, thereby unambiguously confirming the identities of 3 and 4. In summary, this work provides a foundation for mass spectrometry-based characterization of new C-CTXs, including a suite of simple chemical reactions to assist the examination of structural modifications.

The Terroir of Cannabis: Terpene Metabolomics as a Tool to Understand Cannabis sativa Selections.

The phytochemical diversity of Cannabis chemovars is not well understood, and many chemovars were created in informal breeding programs without records of parentage or the criteria for selection. Key criteria for selection sometimes included aroma notes and visual cues, which some breeders associated with pharmacological activity. We hypothesized that the process of selection for scents believed to be related to specific tetrahydrocannabinol levels has resulted in modified terpene biosynthesis in these chemovars. Thirty-two cannabinoids, 29 monoterpenes and 38 sesquiterpenes were measured in 33 chemovars from 5 licensed producers. A classification system based on cannabinoid content was used with targeted metabolomic tools to determine relationships in the phytochemistry. Three monoterpenes, limonene, ß-myrcene, and α-pinene, and two sesquiterpenes, caryophyllene and humulene, were abundant in the majority of chemovars. Nine terpenes were present in tetrahydrocannabinol-dominant chemovars. Three monoterpenes and four sesquiterpenes were predominantly found in cannabidiol-containing chemovars. Low abundance terpenes may have been the aromatic cues identified by breeders. The medicinal activity of some of the terpenes is likely to contribute to the pharmacological effect of specific chemovars. Together, these data demonstrate the synergy of compounds in Cannabis chemovars and point to the need for additional research to understand the phytochemical complexity.

Leaner and greener analysis of cannabinoids.

There is an explosion in the number of labs analyzing cannabinoids in marijuana (Cannabis sativa L., Cannabaceae) but existing methods are inefficient, require expert analysts, and use large volumes of potentially environmentally damaging solvents. The objective of this work was to develop and validate an accurate method for analyzing cannabinoids in cannabis raw materials and finished products that is more efficient and uses fewer toxic solvents. An HPLC-DAD method was developed for eight cannabinoids in cannabis flowers and oils using a statistically guided optimization plan based on the principles of green chemistry. A single-laboratory validation determined the linearity, selectivity, accuracy, repeatability, intermediate precision, limit of detection, and limit of quantitation of the method. Amounts of individual cannabinoids above the limit of quantitation in the flowers ranged from 0.02 to 14.9% w/w, with repeatability ranging from 0.78 to 10.08% relative standard deviation. The intermediate precision determined using HorRat ratios ranged from 0.3 to 2.0. The LOQs for individual cannabinoids in flowers ranged from 0.02 to 0.17% w/w. This is a significant improvement over previous methods and is suitable for a wide range of applications including regulatory compliance, clinical studies, direct patient medical services, and commercial suppliers.

Single-Laboratory Validation for the Determination of Flavonoids in Hawthorn Leaves and Finished Products by LC-UV.

Suitably validated analytical methods that can be used to quantify medicinally active phytochemicals in natural health products are required by regulators, manufacturers, and consumers. Hawthorn (Crataegus) is a botanical ingredient in natural health products used for the treatment of cardiovascular disorders. A method for the quantitation of vitexin-2″-O- rhamnoside, vitexin, isovitexin, rutin, and hyperoside in hawthorn leaf and flower raw materials and finished products was optimized and validated according to AOAC International guidelines. A two-level partial factorial study was used to guide the optimization of the sample preparation. The optimal conditions were found to be a 60-minute extraction using 50 : 48 : 2 methanol : water : acetic acid followed by a 25-minute separation using a reversed-phased liquid chromatography column with ultraviolet absorbance detection. The single-laboratory validation study evaluated method selectivity, accuracy, repeatability, linearity, limit of quantitation, and limit of detection. Individual flavonoid content ranged from 0.05 mg/g to 17.5 mg/g in solid dosage forms and raw materials. Repeatability ranged from 0.7 to 11.7 % relative standard deviation corresponding to HorRat ranges from 0.2 to 1.6. Calibration curves for each flavonoid were linear within the analytical ranges with correlation coefficients greater than 99.9 %. Herein is the first report of a validated method that is fit for the purpose of quantifying five major phytochemical marker compounds in both raw materials and finished products made from North American (Crataegus douglasii) and European (Crataegus monogyna and Crataegus laevigata) hawthorn species. The method includes optimized extraction of samples without a prolonged drying process and reduced liquid chromatography separation time.

Optimization and single-laboratory validation of a method for the determination of flavonolignans in milk thistle seeds by high-performance liquid chromatography with ultraviolet detection.

Seeds of milk thistle, Silybum marianum (L.) Gaertn., are used for treatment and prevention of liver disorders and were identified as a high priority ingredient requiring a validated analytical method. An AOAC International expert panel reviewed existing methods and made recommendations concerning method optimization prior to validation. A series of extraction and separation studies were undertaken on the selected method for determining flavonolignans from milk thistle seeds and finished products to address the review panel recommendations. Once optimized, a single-laboratory validation study was conducted. The method was assessed for repeatability, accuracy, selectivity, LOD, LOQ, analyte stability, and linearity. Flavonolignan content ranged from 1.40 to 52.86% in raw materials and dry finished products and ranged from 36.16 to 1570.7 µg/mL in liquid tinctures. Repeatability for the individual flavonolignans in raw materials and finished products ranged from 1.03 to 9.88% RSDr, with HorRat values between 0.21 and 1.55. Calibration curves for all flavonolignan concentrations had correlation coefficients of >99.8%. The LODs for the flavonolignans ranged from 0.20 to 0.48 µg/mL at 288 nm. Based on the results of this single-laboratory validation, this method is suitable for the quantitation of the six major flavonolignans in milk thistle raw materials and finished products, as well as multicomponent products containing dandelion, schizandra berry, and artichoke extracts. It is recommended that this method be adopted as First Action Official Method status by AOAC International.

Recent accomplishments in wound healing.

The challenge to balance limited resources with infinite demand has encouraged an evolution in the way health care services are managed and operated. Chronic wound management is complex and prolonged, and places a considerable financial burden on health services. A typical driver of cost includes the necessity to change dressings on a regular basis. Over the last few decades, several scientific and biological advances have furthered the development of wound care products and facilitated wound management. This article investigates some of the major advancements that have occurred within the wound-care arena during the last 5 years and how these advancements are being translated to provide better delivery of clinical care to patients.

A randomized controlled trial of larval therapy for the debridement of leg ulcers: results of a multicenter, randomized, controlled, open, observer blind, parallel group study.

It has been known for centuries that the application of larvae is useful to heal certain wounds by facilitating debridement of necrotic tissue,(1) yet the efficacy of larval therapy continues to be debatable. This study compared the clinical effectiveness of a larval therapy dressing (BioFOAM) with a standard debridement technique (Purilon gel; hydrogel) in terms of time to debridement of venous (VLU) or mixed arterial/venous (MLU) leg ulcers. Data analyses were conducted on 88 subjects. Sixty-four subjects completed the full study. Of these, 31 of the 32 (96.9%) patients who completed treatment in the larvae arm debrided fully, compared with 11 of the 32 (34.4%) patients who completed the hydrogel arm. In addition, 42 (48%) ulcers fully debrided within the 21-day intervention phase, 31 (67.4%) from the larvae arm (n = 46), and 11 (26.2%) from the hydrogel arm (n = 42), which was statistically significant (p = 0.001) in support of larvae. A statistically significant difference was also observed between treatment arms with regard to numbers of dressing changes during the intervention phase of the study (p < 0.001) in that subjects in the larvae arm required significantly fewer dressing changes(mean = 2.83) than those in the hydrogel arm (mean = 5.40). There were no statistically significant differences in the clinical condition of the wound bed and surrounding skin by intervention. Subjects in the larvae arm experienced more ulcer-related pain or discomfort than subjects in the hydrogel arm (p < 0.001). This study provided good evidence to show that larval therapy, in the form of a BioFOAM dressing, debrided VLU and MLU considerably more quickly than a hydrogel, although the possibility of resloughing should be closely monitored.

Diabetic foot ulcers treated with hyperbaric oxygen therapy: a review of the literature.

Hyperbaric oxygen therapy (HBO) has been used as an adjunct for healing diabetic foot ulcers (DFUs) for decades. However, its use remains controversial. A literature search was conducted to locate clinical studies and assess the available evidence. Ten prospective and seven retrospective studies evaluating HBO for DFUs were located. These were reviewed and the outcomes were discussed. One study reported no difference in outcomes between patients receiving hyperbaric oxygen and the control group. However, their regime differed from all other studies in that the patients received hyperbaric oxygen twice rather than once daily. Reduced amputation rates and improved healing were the most common outcomes observed.

3-Epimers of Caribbean ciguatoxins in fish and algae.

Ciguatera poisoning (CP) is endemic to several subtropical and tropical regions and is caused by the consumption of fish contaminated with ciguatoxins (CTXs). The recent discovery of Caribbean CTXs (C-CTXs) in Gambierdiscus spp. isolated from the Caribbean resulted in the identification of a precursor analogue, C-CTX5, that is reduced into C-CTX1. C-CTX5 has two reducible sites, a ketone at C-3 and hemiketal at C-56. Chemical reductions of C-CTX5 into C-CTX3/4 resulted in two peaks in the LC-HRMS chromatograms with a ratio that differed markedly from that observed in fish extracts and the reduction of C-CTX1 isolated from fish. Reduction of C-CTX5 should have produced four diastereoisomers of C-CTX3/4, prompting a more detailed study of the reduction products. LC-HRMS with a slow gradient was used to separate and detect the four stereoisomers of C-CTX3/4, and to determine the distribution of these analogues in naturally contaminated fish tissues and following chemical reduction of isolated analogues. The results showed that in naturally contaminated fish tissues C-CTX1/2 is a mixture of two diastereoisomers at C-3 and that C-CTX3/4 is a mixture of two pairs of diastereoisomers at C-3 and C-56. The data suggests that there is variability in the enzymatic reduction at C-3 and C-56 of C-CTXs in reef fish, leading to variations in the ratios of the four stereoisomers. Based on these findings, a naming convention for C-CTXs is proposed which aligns with that used for Pacific CTX congeners and will aid in the identification of the structure and stereochemistry of the different CTX analogues.

Purification of Phenylalkanoids and monoterpene glycosides from Rhodiola rosea L. roots by high-speed counter-current chromatography.

INTRODUCTION: Rhodiola rosea L. is a medicinal herb used for its adaptogenic properties. The main active components are the phenylpropanoids collectively referred to as rosavins. OBJECTIVES: To develop an isolation method for phytochemicals present in Rhodiola rosea roots using high-speed counter-current chromatography (HSCCC). METHODOLOGY: The roots of Rhodiola rosea were extracted with methanol and fractionated using liquid-liquid partition and polyamide column clean-up. The purified fraction (100 mg) was subjected to semi-preparative HSCCC using the two-phase solvent system ethyl acetate:butanol:water (3:2:5). The head-to-tail elution mode was employed with a flow rate of 1.5 mL/min and a rotary speed of 1000 rpm. RESULTS: The separation yielded six main fractions with four components more than 90% pure. The sixth fraction was further purified using semi-preparative HPLC with a Synergi-hydro RP C18 -column to obtain rosin and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-ß-d-glucopyranoside. The main components isolated were rosavin (3.4 mg, 97% purity), salidroside (0.5 mg, 90% purity), benzyl-O-ß-d-glucopyranoside (1.2 mg, 85% purity), rosarin (1.3 mg, 99% purity), rosiridin (1.8 mg, 92% purity), rosin (1.2 mg, 95% purity) and geranyl 1-O-α-l-arabinopyranosyl(1 → 6)-ß-d-glucopyranoside (6.5 mg, 97% purity). The identity and purity of these components were confirmed using ultrafast liquid chromatography-diode-array detector-MS/MS analysis, ¹H- and ¹³C-NMR spectroscopy. CONCLUSION: High-speed counter-current chromatography was successful in the isolation of several phytochemicals present in Rhodiola rosea roots, including two components that are not commercially available.

The national health-care agenda in relation to negative pressure wound therapy.

The NHS was founded upon the principle of providing health care for all, regardless of financial status. However, it has reached a point where patient demands are outgrowing NHS resources, causing conflict. Chronic wound management represents a considerable financial burden on health services in terms of manpower requirement, equipment, specialist opinion, and adjunct therapies, such as negative pressure wound therapy (NPWT). Although funding bodies often perceive NPWT to be expensive, there is evidence that if used appropriately it leads to faster healing, early discharge and better quality of life for patients with chronic wounds. However, it must be acknowledged that the type and quality of studies are mixed. Further evidence is required to justify the use of NPWT in chronic wounds in the primary and secondary health-care setting.

Algal ciguatoxin identified as source of ciguatera poisoning in the Caribbean.

Ciguatera poisoning (CP) is a severe seafood-borne disease, caused by the consumption of reef fish contaminated with Caribbean ciguatoxins (C-CTXs) in the Caribbean and tropical Atlantic. However, C-CTXs have not been identified from their presumed algal source, so the relationship to the CTXs in fish causing illness remains unknown. This has hindered the development of detection methods, diagnostics, monitoring programs, and limited fundamental knowledge on the environmental factors that regulate C-CTX production. In this study, in vitro and chemical techniques were applied to unambiguously identify a novel C-CTX analogue, C-CTX5, from Gambierdiscus silvae and Gambierdiscus caribaeus strains from the Caribbean. Metabolism in vitro by fish liver microsomes converted algal C-CTX5 into C-CTX1/2, the dominant CTX in ciguatoxic fish from the Caribbean. Furthermore, C-CTX5 from G. silvae was confirmed to have voltage-gated sodium-channel-specific activity. This finding is crucial for risk assessment, understanding the fate of C-CTXs in food webs, and is a prerequisite for development of effective analytical methods and monitoring programs. The identification of an algal precursor produced by two Gambierdiscus species is a major breakthrough for ciguatera research that will foster major advances in this important seafood safety issue.

A retrospective study of diabetic foot ulcers treated with hyperbaric oxygen therapy.

A retrospective review of patient medical records was conducted to assess what factors influence the outcomes of diabetic foot ulcers treated with hyperbaric oxygen (HBO) therapy. Patients referred to the Diving Diseases Research Centre for HBO therapy for the treatment of diabetic foot ulcers during a 2-year period were included in this study. Data collected from 30 sets of patient records were entered into SPSS and statistical analysis was undertaken to investigate whether any underlying pathologies or confounding factors appeared to influence patient outcome. A 73.3% of patients achieved a successful outcome of partial healing, major amputation no longer required, amputation level lower than anticipated prior to HBO or healing at the end of HBO therapy and 70% remained successful 3 months later. A 13.3% of patients were lost to follow-up at 3 months and one patient (3.3%) had a major amputation. Steroid therapy, peripheral vascular disease, previous minor amputation, type of diabetes, previous HBO therapy, larvae therapy, the use of interactive dressings and haemoglobin A1c levels were all observed to have had a significant relationship with patient outcome (P < 0.05). These results were compared with data from other published research conducted in this area on similar patient groups. A larger scale study focussing on the factors found to be significant in this study is recommended. An improvement of patient documentation would allow patient outcomes to be more consistently monitored in the future.

Selective and Efficient Capture and Release of vic-Diol-Containing Pacific and Caribbean Ciguatoxins from Fish Extracts with a Boronate Affinity Polymer.

Ciguatera poisoning can occur following the consumption of fish contaminated with trace levels of ciguatoxins (CTXs). These trace levels represent an analytical challenge for confirmation by LC-MS due to matrix interferences and the high instrument sensitivity required. Sample preparation procedures are laborious and require extensive cleanup procedures to address these issues. The application of a selective isolation technique employing boronate affinity polymers was therefore investigated for the capture of vic-diol-containing Caribbean and Pacific CTXs from fish extracts. A dispersive SPE procedure was developed where nearly complete binding of CTXs in fish extracts occurred with boric acid gel in less than 1 h. Release of the bound CTXs resulted in >95% recovery of C-CTX1/2, C-CTX3/4, CTX1B, 54-deoxyCTX1B, and 52-epi-54-deoxyCTX1B from the extracts. This selective extraction tool has the potential to greatly simplify both analytical sample preparation and preparative extraction and isolation of CTXs for structure elucidation and production of standards.

Psychological Stress on Wound Healing: A Silent Player in a Complex Background.

Stress is hard to define and is further complicated by varied perceptions in the population and differing responses in different situations. Psychological stress brings about certain physiological changes through manipulation of the neural, humoral and immunological systems. Observational studies have showed that fear and anxiety before surgery can complicate normal wound healing. Two different pathways appear to be involved: one directly through hypothalamic-pituitary-adrenal axis and sympathetic-adrenomedullary axis, and another indirectly through negative psychological stressors such as anxiety, depression and social isolation. The pathogenesis includes decreased expression of pro-inflammatory cytokines, resulting in poor angiogenesis, matrix regeneration and delayed healing. Prolonged immunological activation in itself is a stressor and can precipitate a sickness behaviour syndrome manifested by disturbed sleep, anorexia, reduction in activity, increased responsiveness to pain and addiction to alcohol and tobacco. It has been observed that cortisol release suppresses pro-inflammatory cytokine release, while down-regulation of cortisol causes unabated inflammatory response. In individuals with chronic wounds, on the other hand, it is thought that physical stress has different effects such as foul odor, pain, exudate and social and familial isolation, which may act independently as psychological stressors. This article attempts to appraise the influence of psychological stress on the immunological system and its effect on wound healing.

Selective extraction of gambierone and related metabolites in Gambierdiscus silvae using m-aminophenylboronic acid-agarose gel and liquid chromatography-high-resolution mass spectrometric detection.

Gambierdiscus spp. are epi-benthic dinoflagellates that have been associated with ciguatera poisoning. These microalgae can have complex secondary metabolite profiles including ciguatoxins, maitotoxins, and gambierones, with varying compositions and toxicities across species and strains. Given this chemical diversity there is a need to develop selective and sensitive methods for secondary metabolite profiling. In this study, we used a cultured Caribbean strain of Gambierdiscus silvae to develop sample preparation and analysis strategies for characterizing vic-diol containing secondary metabolites. A pooled cellular extract was first screened by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for ciguatoxin-related compounds, which resulted in the confirmation of gambierone (1) and a novel isomer of 44-methylgambierone (3). Treatment of the extract with periodate confirmed that the gambierones each contained one reactive vic-diol, which was exploited for the development of a selective extraction procedure using m-aminophenylboronic acid gel and the non-aqueous binding solvent chloroform. Using this non-traditional boronate affinity procedure, LC-HRMS also revealed the presence of additional sulfated polycyclic ethers in the gambierone-containing vic-diol fraction, while pigments and other contaminants were removed. The developed tools could be applied to screen collections of Gambierdiscus and other benthic algae to provide additional chemical characterization of gambierone-related compounds. The selective extraction procedure may also prove useful as a step in the isolation of these sulfated polyethers for structural, toxicological and biotransformation studies.