The scale of the problem is particularly stark in the United States, where alcohol use disorders alone afflict 29 million individuals and cause more than 140,000 deaths annually. Layered on top of this is the opioid crisis, which claims more than 100,000 lives every year. The COVID-19 pandemic made matters worse. Lockdowns and isolation drove excessive alcohol drinking, drug addiction, opioid overdose and death, and the emergence of so-called Long Hauler symptoms and neuroCOVID disorders has exacerbated substance use disorders as the disease transitions to endemic status. Onaivi argues that bridging the treatment gap and discovering new, more effective medications are urgent priorities that demand fresh research strategies and targets.

One of the most technically intriguing preclinical studies in the Special Issue came from North and colleagues, who examined how alcohol interacts with pregnenolone, a hormone supplement popular among people seeking cognitive and anti-aging benefits. Using male and female C57BL/6J mice, the team investigated the consequences for cerebral arteries in a scenario where humans take pregnenolone supplements while binge drinking. The results showed that pregnenolone at low concentrations synergized with alcohol to constrict the middle cerebral artery, a critical vessel supplying the brain. Remarkably, this synergism disappeared when both substances were studied at higher doses, suggesting a dose-dependent complexity in how the two compounds converge on the same vascular pathway.

Additional in vitro electrophysiological data and measurements of cerebral artery diameter provided evidence that pregnenolone and alcohol act on a common molecular route to evoke artery constriction. Specifically, both compounds inhibit large-conductance calcium- and voltage-gated potassium channels, known as BK channels, by disrupting the allosteric coupling that normally links calcium binding to channel gating. Because pregnenolone regulates several physiological processes, the study highlights that combining the supplement with alcohol may meaningfully impair brain artery function. This is particularly relevant given that alcohol use disorders occur in populations aged 65 and older, who may already be at risk for cerebrovascular ischemic conditions, making the supplement-alcohol interaction a genuine clinical concern rather than a laboratory curiosity.

A second preclinical study, by Roberts and colleagues, shifted attention to the CB2 cannabinoid receptor, a receptor increasingly recognized for its role in inflammation rather than the psychoactive effects typically associated with cannabinoid signaling. The team used conditional knockout mice with selective deletion of CB2 receptors from dopamine neurons and, in a separate group, from microglia, the resident immune cells of the brain. Motor function tests in activity monitors, wheel-running activity, rotarod performance and alcohol preference tests were used to evaluate behavioral alterations induced by alcohol, while ELISA assays measured levels of pro-inflammatory cytokines including tumor necrosis factor-alpha, interleukin-6, interleukin-1alpha and interleukin-1beta in the hippocampus.

The data revealed that cell-type specific deletion of CB2 receptors from dopamine neurons and microglia differentially altered behavioral and alcohol preference outcomes, and that this deletion enhanced alcohol-induced inflammation. Pharmacological intervention with the non-specific cannabinoid agonist WIN55212-2 reduced alcohol preference in both the conditional knockout and wild-type mice. These findings suggest that CB2 receptors modulate behavioral and immune perturbations caused by alcohol and may be exploited as a potential therapeutic target in alcohol use disorders, offering a route to treatment that avoids the psychoactive baggage of CB1 receptor targeting.

Turning to mechanisms that shape addiction across the lifespan, Crews and colleagues reviewed epigenetic regulation of microglia and neurons by proinflammatory signaling following adolescent intermittent ethanol exposure and in human alcohol use disorder. Their review centers on high mobility group box 1, or HMGB1, a cytokine-like molecule associated with brain proinflammatory signals in alcohol-induced changes. Adolescent intermittent ethanol exposure alters neuroimmune gene expression in neurons, microglia and astrocytes, increasing adult drinking and preference, anxiety and reward seeking. HMGB1 activates multiple proinflammatory receptors, including Toll-like receptors, which mediate proinflammatory gene induction. Epigenetic mechanisms of adolescent ethanol exposure have now emerged as drivers of alcohol-induced pathology in both rodents and post-mortem human alcohol use disorder hippocampus, linking adolescent drinking to lifelong signaling associated with pathological behavior and hyperkatifeia, the amplified negative emotional state that fuels addiction.

Two further reviews also focused on adolescent alcohol use. Hauser and colleagues examined how adolescent alcohol and nicotine exposure alters the adult response to alcohol, drawing on basic and clinical human research as well as preclinical rodent models, including alcohol-preferring rat lines. Their review summarized evidence that voluntary alcohol consumption and nicotine exposure during adolescence can promote alcohol consumption during adulthood, and identified mechanisms involving dopamine and cholinergic systems as potential pharmacological targets. Compounds such as varenicline, cholinesterase inhibitors, bupropion, lobeline and cytisine may reverse or prevent some of the deleterious adult changes following adolescent exposure. Getachew and colleagues, meanwhile, explored the growing importance of the bidirectional gut-brain axis, focusing on how adolescent alcohol use reshapes the gut microbiota. Dysbiosis, gut microbiome-microglia interactions and Toll-like receptor signaling suggest that crosstalk between the gut and brain may influence fetal alcohol spectrum disorder and adult alcohol use disorder, positioning the gut microbiome, nutrients and GPCR signaling as emerging therapeutic targets.

Rounding out the Special Issue, Vigorito and Chang reviewed alcohol use and the pain system, examining how nociception, nociceptive pain sensation and pain perception contribute to alcohol use, misuse and dependence. Their review covered the effects of alcohol at all levels of the pain system, from neuroimmune interactions and molecular aspects of nociception to spinal, supraspinal and affective-emotional circuits, along with maladaptive homeostasis and allostasis that drive the progression of alcohol use disorders. Taken together, the two research articles and four review articles in the Special Issue provide preclinical data and comprehensive discussion of multiple mechanisms associated with the effects of drugs and alcohol, while highlighting the treatment gaps that persist for substance use disorders.

Looking forward, Onaivi points to generative Artificial Intelligence systems as promising tools to improve individual health outcomes by streamlining diagnosis and treatment with clinical applications. While generative AI holds potential in the field of substance use disorders, caution is required as the functionalities of AI continue to evolve, as do the challenges of substance use disorders themselves. AI systems beyond ChatGPT, combined with advanced sensing and large quantitative approaches, may offer useful opportunities to identify more urgent and effective treatment medications for substance use disorders. As the research presented at the IDARS conference and captured in this Special Issue demonstrates, the path to better addiction treatment will likely require converging insights from vascular biology, neuroimmunology, epigenetics, the gut microbiome and computational science, each contributing pieces to a puzzle that has resisted simple solutions for decades.

Subject of Research: Neuroscience

Article Title: Editorial: 8th biennial international drug and alcohol research society conference 2022

Article References: Onaivi, E. S. (2025). Editorial: 8th biennial international drug and alcohol research society conference 2022. Advances in Drug and Alcohol Research, 4, Article 13706. https://doi.org/10.3389/adar.2024.13706

Image Credits: AI Generated

DOI: 10.3389/adar.2024.13706

Keywords: addiction, alcohol use disorder, substance use disorder, CB2 cannabinoid receptors, gut microbiome, epigenetics, neuroimmune signaling, pregnenolone, BK channels, artificial intelligence, Editorial, biennial

The study, published open access in Discover Chemistry, set out to close a conspicuous knowledge gap. While close relatives such as Isodon rubescens have been extensively characterized—yielding celebrated diterpenoids like oridonin that have attracted attention for anti-inflammatory and cytoprotective effects—I. coesta has remained comparatively obscure despite its wide distribution across Bangladesh, Nepal, India, China, Myanmar, the Philippines, Indonesia, Sri Lanka, and Thailand. The researchers harvested whole plants, excluding roots, in September 2023, air-dried them for two to four days, ground them into a fine powder, and extracted the material separately with methanol and hexane over ten to fifteen days of soaking. The polar solvent proved far more generous: the methanolic extract yielded 4.02 percent by weight, while the nonpolar hexane extract yielded only 1.10 percent, a difference that foreshadowed the chemistry to come.

Gas chromatography–mass spectrometry, performed at the Advanced Instrumentation Research Facility at Jawaharlal Nehru University in New Delhi on a Shimadzu GCMS-QP2010 Plus system with a DB-5 capillary column, identified 24 compounds in each extract. In the methanolic extract, these accounted for 81.93 percent of total composition, with the acyclic diterpene alcohol phytol dominating at 12.22 percent, followed by the steroid precursor pregnenolone acetate at 7.54 percent, squalene at 6.83 percent, and methyl linolenate at 6.51 percent. The hexane extract told a different story: squalene, a triterpene hydrocarbon famous for its antioxidant and skin-protective properties, led at 11.79 percent, with the long-chain hydrocarbon 2-methylhexacosane close behind at 9.68 percent, and hexatriacontane, propylene glycol monooleate, and palmitic acid rounding out the major peaks. Seven compounds appeared in both extracts, including phytol, squalene, neophytadiene, and vitamin E, suggesting overlapping biochemical pathways that persist regardless of solvent polarity.

The identity of the dominant molecules matters because several of them carry well-documented biological credentials. Phytol serves as a biosynthetic precursor to vitamins E and K1 and has reported antioxidant, anti-inflammatory, and anticancer activities. Pregnenolone acetate sits upstream in the biosynthesis of steroid hormones and has been studied for neuroprotective and anti-inflammatory effects, making it a molecule of interest in neuropharmacology and endocrinology. Squalene, meanwhile, is an intermediate in sterol biosynthesis and a widely used emollient in cosmetics and pharmaceuticals. The presence of gamma-sitosterol, tocopherol, and linoleic acid derivatives in the methanolic extract further enriches the profile of a plant whose chemical inventory had previously been little more than a footnote in the Isodon literature.

Quantitative colorimetric assays confirmed that polarity drives the phytochemical harvest. The methanolic extract registered a total phenolic content of 31.37 milligrams of gallic acid equivalents per gram, a total flavonoid content of 313.28 milligrams of quercetin equivalents per gram, and a total antioxidant capacity of 8.61 milligrams of ascorbic acid equivalents per gram. The hexane extract trailed on every measure, with 17.19 milligrams GAE per gram of phenolics, 117.57 milligrams QE per gram of flavonoids, and 2.07 milligrams AAE per gram of antioxidant capacity. The pattern is chemically intuitive: methanol, being polar, efficiently pulls phenols and flavonoids out of plant tissue, whereas hexane preferentially dissolves lipids, waxes, and terpenoid hydrocarbons. Flavonoids, in particular, are major contributors to plant antioxidant activity, so their concentration in the methanolic fraction is consistent with the rest of the data.

The radical-scavenging results, however, temper any temptation to crown the plant a super-antioxidant. In the DPPH assay, which tracks the reduction of a stable violet free radical by measuring absorbance at 517 nanometers, the methanolic extract posted an IC50 of 748.38 micrograms per milliliter and the hexane extract 794.13 micrograms per milliliter. Those figures indicate moderate to weak activity compared with ascorbic acid, the reference standard, which achieved an IC50 of just 74.72 micrograms per milliliter. Two-way ANOVA showed that concentration strongly influenced scavenging activity, with a highly significant effect, while the difference between the two extract types alone did not reach statistical significance, though a significant interaction between extract type and concentration revealed concentration-dependent divergence in their responses. The authors caution that direct comparison with the standard should be interpreted carefully because different concentration ranges were used for the plant extracts and the reference compound.

To probe how the major constituents might behave at the molecular level, the team turned to computational docking against two enzymes that sit at opposite ends of the oxidative-stress balance. Human peroxiredoxin-5, resolved by X-ray crystallography at 1.50 angstrom resolution, is a thioredoxin-family antioxidant enzyme that detoxifies hydrogen peroxide and peroxynitrite, defending cells against oxidative injury. NADPH oxidase, resolved at 1.80 angstroms, is the enzymatic engine of reactive oxygen species generation, and its overactivation drives inflammatory damage. Using PyRx 0.8 with AutoDock Vina, the researchers docked phytol, pregnenolone acetate, squalene, and 2-methylhexacosane into both binding pockets. Pregnenolone emerged as the clear frontrunner, binding peroxiredoxin-5 at minus 6.1 kilocalories per mole and NADPH oxidase at minus 8.4 kilocalories per mole through a mix of hydrogen bonds, pi-anion, and pi-alkyl contacts. Phytol followed with moderate affinities, while 2-methylhexacosane performed worst, managing only minus 3.0 and minus 5.7 kilocalories per mole through weak van der Waals and alkyl interactions.

The ADMET analysis added a sobering pharmacokinetic dimension. All four compounds passed the molecular-weight criterion of Lipinski’s rule of five, but squalene, phytol, and 2-methylhexacosane showed MLOGP values far above the acceptable ceiling of 4.15, signaling extreme lipophilicity that predicts poor aqueous solubility and low gastrointestinal absorption. Pregnenolone was the only compound predicted to have high GI absorption, the only one expected to cross the blood–brain barrier, and the only one that is not a P-glycoprotein substrate, making it the most drug-like molecule in the set. Toxicity predictions from ProTox 3.0 were reassuring across the board: none of the compounds showed hepatotoxicity, carcinogenicity, or AMES mutagenicity, and squalene and phytol carried LD50 values of 5,000 milligrams per kilogram, indicating generous safety margins. The authors suggest that nanoemulsions, liposomes, solid lipid nanoparticles, or phospholipid-based delivery systems could rescue the bioavailability of the lipophilic constituents.

The researchers are careful to frame the docking results as hypothesis-generating rather than proof of pharmacological activity, and they recommend in vivo validation, molecular dynamics simulations, and quantitative phytochemical confirmation by HPLC or LC–MS as the necessary next steps. Even with those caveats, the study positions Isodon coesta as a flavonoid-rich reservoir of bioactive metabolites from one of the world’s great biodiversity hotspots—the Indian Himalayan region harbors roughly half of India’s flowering plant species with nearly 30 percent endemism, and Uttarakhand alone supports more than 5,000 vascular plant species. As computational screening increasingly complements fieldwork in natural-product drug discovery, this aromatic undershrub of the Himalayan slopes may yet translate its ethnobotanical reputation into molecules worthy of the laboratory bench and, eventually, the clinic.

Subject of Research: Phytochemical profiling and computational antioxidant evaluation of Isodon coesta from the Uttarakhand Himalaya

Article Title: Comprehensive phytochemical profiling, molecular interaction studies, and ADMET analysis of hexane and methanol extracts of Isodon coesta from Uttarakhand’s Himalayan Region

Article References: Mawri, D., Pujari, R., Bahuguna, A., Rawat, D. S., Prakash, O., Kumar, R., & Dubey, S. K. (2026). Comprehensive phytochemical profiling, molecular interaction studies, and ADMET analysis of hexane and methanol extracts of Isodon coesta from Uttarakhand’s Himalayan Region. Discover Chemistry, 3(1), Article 558. https://doi.org/10.1007/s44371-026-01003-x

Image Credits: AI Generated

DOI: 10.1007/s44371-026-01003-x

Keywords: Isodon coesta, phytochemistry, GC-MS, antioxidant, molecular docking, ADMET, Uttarakhand, Himalayan medicinal plants, phytol, pregnenolone, squalene, Lamiaceae