Ma H et al. (2016) Neurochem Res "Effects of a Standardized Phenolic-Enriched Maple Syrup Extract on -Amyloid Aggregation, Neuroinflammation in Microglial and Neuronal Cells, and -Amyloid Induced Neurotoxicity in Caenorhabditis elegans."

Liu Y, Seeram NP, DaSilva NA, Pham PT, Wei Z, Liu W, Nahar PP, Ma H, Vattem DA, Crews R, Shaikh ZA, Slitt AL

[Neurochem Res, 2016]

Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid 1-42 peptide (A1-42) fibrillation in a concentration-dependent manner (50-500g/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5% at 500g/mL vs. 77.3% at 50g/mL, respectively). MSX (100g/mL) decreased H2O2-induced oxidative stress (16.1% decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6% decrease in NOS, IL-6, PGE2, and TNF levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100g/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8% compared to media collected from LPS-BV-2 treated cells. Also, MSX (10g/mL) showed protective effects against A1-42 induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.

Johnson SL et al. (2018) Nutrients "Levodopa-Reduced Mucuna pruriens Seed Extract Shows Neuroprotective Effects against Parkinson's Disease in Murine Microglia and Human Neuroblastoma Cells, Caenorhabditis elegans, and Drosophila melanogaster."

Vattem DA, Park HY, Ma H, Johnson SL, Seeram NP, DaSilva NA

[Nutrients, 2018]

<i>Mucuna pruriens</i> (Mucuna) has been prescribed in Ayurveda for various brain ailments including 'kampavata' (tremors) or Parkinson's disease (PD). While Mucuna is a well-known natural source of levodopa (L-dopa), published studies suggest that other bioactive compounds may also be responsible for its anti-PD effects. To investigate this hypothesis, an L-dopa reduced (&lt;0.1%) <i>M. pruriens</i> seeds extract (MPE) was prepared and evaluated for its anti-PD effects in cellular (murine BV-2 microglia and human SH-SY5Y neuroblastoma cells), <i>Caenorhabditis elegans</i>, and <i>Drosophila melanogaster</i> models. In BV-2 cells, MPE (12.550 g/mL) reduced hydrogen peroxide-induced cytotoxicity (15.7-18.6%), decreased reactive oxygen species production (29.1-61.6%), and lowered lipopolysaccharide (LPS)-induced nitric oxide species release by 8.960%. MPE (12.5-50 g/mL) mitigated SH-SY5Y cell apoptosis by 6.9-40.0% in a non-contact co-culture assay with cell-free supernatants from LPS-treated BV-2 cells. MPE (12.5-50 g/mL) reduced 6-hydroxydopamine (6-OHDA)-induced cell death of SH-SY5Y cells by 11.8538.5%. Furthermore, MPE (12.5-50 g/mL) increased median (25%) and maximum survival (47.8%) of <i>C. elegans</i> exposed to the dopaminergic neurotoxin, methyl-4-phenylpyridinium. MPE (40 g/mL) ameliorated dopaminergic neurotoxin (6-OHDA and rotenone) induced precipitation of innate negative geotaxis behavior of <i>D. melanogaster</i> by 35.3 and 32.8%, respectively. Therefore, MPE contains bioactive compounds, beyond L-dopa, which may impart neuroprotective effects against PD.

Prithiviraj B et al. (2005) Infect Immun "Down regulation of virulence factors of Pseudomonas aeruginosa by salicylic acid attenuates its virulence on Arabidopsis thaliana and Caenorhabditis elegans."

Bais HP, Schweizer HP, Dayakar BV, Najarro EH, Vivanco JM, Prithiviraj B, Weir T, Suresh B

[Infect Immun, 2005]

Salicylic acid (SA) is a phenolic metabolite produced by plants and is known to play an important role in several physiological processes, such as the induction of plant defense responses against pathogen attack. Here, using the Arabidopsis thaliana-Pseudomonas aeruginosa pathosystem, we provide evidence that SA acts directly on the pathogen, down regulating fitness and virulence factor production of the bacteria. Pseudomonas aeruginosa PA14 showed reduced attachment and biofilm formation on the roots of the Arabidopsis mutants lox2 and cpr5-2, which produce elevated amounts of SA, as well as on wild-type Arabidopsis plants primed with exogenous SA, a treatment known to enhance endogenous SA concentration. Salicylic acid at a concentration that did not inhibit PA14 growth was sufficient to significantly affect the ability of the bacteria to attach and form biofilm communities on abiotic surfaces. Furthermore, SA down regulated three known virulence factors of PA14: pyocyanin, protease, and elastase. Interestingly, P. aeruginosa produced more pyocyanin when infiltrated into leaves of the Arabidopsis transgenic line NahG, which accumulates less SA than wild-type plants. This finding suggests that endogenous SA plays a role in down regulating the synthesis and secretion of pyocyanin in vivo. To further test if SA directly affects the virulence of P. aeruginosa, we used the Caenorhabiditis elegans-P. aeruginosa infection model. The addition of SA to P. aeruginosa lawns significantly diminished the bacterium''s ability to kill the worms, without affecting the accumulation of bacteria inside the nematodes'' guts, suggesting that SA negatively affects factors that influence the virulence of P. aeruginosa. We employed microarray technology to identify SA target genes. These analyses showed that SA treatment affected expression of 331 genes. It selectively repressed transcription of exoproteins and other virulence factors, while it had no effect on expression of housekeeping genes. Our results indicate that in addition to its role as a signal molecule in plant defense responses, SA works as an anti-infective compound by affecting the physiology of P. aeruginosa and ultimately attenuating its virulence.

Liu W et al. (2016) Neurochem Int "Development of a neuroprotective potential algorithm for medicinal plants."

Dain JA, DaSilva NA, Zhang L, Rose KN, Wan C, Johnson SL, Liu W, Ma H, Seeram NP

[Neurochem Int, 2016]

Medicinal plants are promising candidates for Alzheimer's disease (AD) research but there is lack of systematic algorithms and procedures to guide their selection and evaluation. Herein, we developed a Neuroprotective Potential Algorithm (NPA) by evaluating twenty-three standardized and chemically characterized Ayurvedic medicinal plant extracts in a panel of bioassays targeting oxidative stress, carbonyl stress, protein glycation, amyloid beta (A) fibrillation, acetylcholinesterase (AChE) inhibition, and neuroinflammation. The twenty-three herbal extracts were initially evaluated for: 1) total polyphenol content (Folin-Ciocalteu assay), 2) free radical scavenging capacity (DPPH assay), 3) ferric reducing antioxidant power (FRAP assay), 4) reactive carbonyl species scavenging capacity (methylglyoxal trapping assay), 5) anti-glycative effects (BSA-fructose, and BSA-methylglyoxal assays) and, 6) anti-A fibrillation effects (thioflavin-T assay). Based on assigned index scores from the initial screening, twelve extracts with a cumulative NPA score 40 were selected for further evaluation for their: 1) inhibitory effects on AChE activity, 2) in vitro anti-inflammatory effects on murine BV-2 microglial cells (Griess assay measuring levels of lipopolysaccharide-induced nitric oxide species), and 3) in vivo neuroprotective effects on Caenorhabditis elegans post induction of A1-42 induced neurotoxicity and paralysis. Among these, four extracts had a cumulative NPA score 60 including Phyllanthus emblica (amla; Indian gooseberry), Mucuna pruriens (velvet bean), Punica granatum (pomegranate) and Curcuma longa (turmeric; curcumin). These extracts also showed protective effects on H2O2 induced cytotoxicity in differentiated cholinergic human neuronal SH-SY5Y and murine BV-2 microglial cells and reduced tau protein levels in the SH-SY5Y neuronal cells. While published animal data support the neuroprotective effects of several of these Ayurvedic medicinal plant extracts, some remain unexplored for their anti-AD potential. Therefore, the NPA may be utilized, in part, as a strategy to help guide the selection of promising medicinal plant candidates for future AD-based research using animal models.

Liu Y et al. (2017) J Agric Food Chem "Isolation, Identification, and Biological Evaluation of Phenolic Compounds from the Traditional North American Confectionery, Maple Sugar."

Seeram NP, Dasilva N, Rose K, Liu Y, Johnson S

[J Agric Food Chem, 2017]

Maple sap, collected from the sugar maple (Acer saccharum) tree, is boiled to produce the popular plant-derived sweetener, maple syrup, which can then be further evaporated to yield the traditional North American confectionery, maple sugar. While maple sap and maple syrup have been previously studied, the phytochemical constituents of maple sugar are unknown. Herein, thirty phenolic compounds, 1-30, primarily lignans, were isolated and identified (by HRESIMS and NMR) from maple sugar. The isolates included the phenylpropanoid-based lignan tetramers, (erythro,erythro)-4'',4'''-dihydroxy-3,3',3'',3''',5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8'';4',8'''-bisoxy-8,8'-dineolignan-7'',7''',9'',9'''-tetraol, 29, and (threo,erythro)-4'',4'''-dihydroxy-3,3',3'',3''',5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8'';4',8'''-bisoxy-8,8'-dineolignan-7'',7''',9'',9'''-tetraol, 30, neither of which have been identified from maple sap or maple syrup before. Twenty of the isolates (selected based on sample quantity available) were evaluated for their potential biological effects against lipopolysaccharide-induced inflammation in BV-2 microglia in vitro and juglone-induced oxidative stress in Caenorhabditis elegans in vivo. The current study increases scientific knowledge of possible bioactive compounds present in maple-derived foods including maple sugar.

van Es-Remers M et al. (2022) J Cannabis Res "C. elegans as a test system to study relevant compounds that contribute to the specific health-related effects of different cannabis varieties."

ILiopoulou E, Spadaro JA, Korthout H, Poppelaars E, Wildwater M, van Haaster M, Kim HK, van Es-Remers M, de Wit M

[J Cannabis Res, 2022]

BACKGROUND: -tetrahydrocannabinol (THC) and cannabidiol (CBD). Evidence for putative entourage effects caused by other compounds present in cannabis is hard to obtain due to the subjective nature of patient experience data. Caenorhabditis elegans (C. elegans) is an objective test system to identify cannabis compounds involved in claimed health and entourage effects. METHODS: From a medicinal cannabis breeding program by MariPharm BV, the Netherlands a set of 12 varieties were selected both THC rich varieties as well as CBD rich varieties. A consecutive extraction process was applied resulting in a non-polar (cannabinoid-rich) and polar (cannabinoid-poor) extract of each variety. The test model C. elegans was exposed to these extracts in a broad set of bioassays for appetite control, body oscillation, motility, and nervous system function. RESULTS: Exposing C. elegans to extracts with a high concentration of cannabinoids (&gt; 1 g/mL) reduces the life span of C. elegans dramatically. Exposing the nematodes to the low-cannabinoid (&lt; 0.005 g/mL) polar extracts, however, resulted in significant effects with respect to appetite control, body oscillation, motility, and nervous system-related functions in a dose-dependent and variety-dependent manner. DISCUSSION: C. elegans is a small, transparent organism with a complete nervous system, behavior and is due to its genetic robustness and short life cycle highly suitable to unravel entourage effects of Cannabis compounds. Although C. elegans lacks an obvious CB1 and CB2 receptor it has orthologs of Serotonin and Vanilloid receptor which are also involved in (endo)cannabinoid signaling. CONCLUSION: By using C. elegans, we were able to objectively distinguish different effects of different varieties despite the cannabinoid content. C. elegans seems a useful test system for studying entourage effects, for targeted medicinal cannabis breeding programs and product development.