Salt-Tolerant Coastal Plants Reveal Potent Antioxidant and Anti-Inflammatory Compounds

Two unassuming plants that thrive in the salt-sprayed marshes of India’s Cuddalore coast are emerging as serious candidates in the search for new antioxidant and anti-inflammatory agents. In a study published in Plant Biosystems, researchers at Bharathidasan University systematically compared extracts of Suaeda maritima, a saltmarsh herb, and Sesuvium portulacastrum, a fleshy shoreline succulent, to assess their phytochemical richness and pharmacological potential. The findings add weight to a growing body of evidence that halophytes, plants adapted to extreme salinity, are among the most chemically interesting and underexploited reservoirs of bioactive molecules in the coastal landscape.

Halophytes occupy one of the most punishing niches in the plant world. Rooted in soils saturated with salt and repeatedly exposed to tidal flooding, intense sunlight and oxidative stress, they must defend themselves with an unusually robust chemical arsenal. That stress-driven metabolism often leads to elevated production of phenolics, flavonoids, tannins and other secondary metabolites, many of which have documented antioxidant, anti-inflammatory and even anticancer properties when tested in laboratory systems. Plants that manufacture these compounds to survive are, in effect, pre-formulating drugs, and the Bharathidasan team set out to quantify exactly how much pharmacological value two representative species carry.

The researchers collected both plants from the Cuddalore coast region of Tamil Nadu and prepared a series of solvent extracts, ranging from non-polar hexane to more polar ethyl acetate and other fractions. Sequential extraction with solvents of increasing polarity is a standard strategy in natural products chemistry because different classes of compounds partition differently: non-polar solvents pull out lipids, terpenoids and certain phenolic derivatives, while more polar solvents recover flavonoid glycosides, tannins and free amino acids. By comparing the same plant across solvents, the team could pinpoint which fraction carried which activity, a critical step for anyone hoping to isolate a single therapeutic molecule later.

The chemical inventory was striking. The ethyl acetate extract of Suaeda maritima recorded the highest total flavonoid content at 272.74 milligrams of quercetin equivalents per gram, alongside 114.32 milligrams of gallic acid equivalents per gram of total phenolics, 95.68 milligrams of tannic acid equivalents per gram of tannins, and 122.43 milligrams of leucine equivalents per gram of free amino acids. These are substantial concentrations for a wild-harvested marsh plant. Flavonoids and phenolic acids are the classical workhorses of plant antioxidant chemistry, capable of donating electrons or hydrogen atoms to neutralise reactive oxygen species, the unstable molecules implicated in inflammation, cardiovascular disease, neurodegeneration and cancer progression.

Bioactivity testing told an equally interesting story, but with a twist in which plant came out ahead. The hexane extract of Sesuvium portulacastrum delivered the strongest radical-scavenging performance in the DPPH assay, with an IC50 value of 63.32 micrograms per millilitre, meaning the concentration needed to neutralise half of the synthetic free radicals in the test. The same hexane fraction also dominated the anti-inflammatory battery of tests: it inhibited heat-induced denaturation of bovine serum albumin with an IC50 of 68.18 micrograms per millilitre, suppressed proteinase activity with an IC50 of 66.21 micrograms per millilitre, and scavenged nitric oxide with an IC50 of 58.65 micrograms per millilitre. Protein denaturation is a hallmark of inflammatory states, and compounds that stabilise protein structure or block proteolytic enzymes are considered useful templates for anti-inflammatory drug development. Nitric oxide, while a vital signalling molecule at physiological levels, becomes a damaging inflammatory mediator when overproduced, so nitric oxide scavenging is another clinically relevant benchmark.

The observation that non-polar hexane fractions produced the strongest functional effects, while polar ethyl acetate fractions carried the highest measured phytochemical content, illustrates a recurring lesson in pharmacognosy: quantity of known marker compounds does not always predict biological potency. Hexane-soluble constituents such as fatty acid derivatives, terpenoids and certain lipophilic phenolics can be disproportionately active even when classical colorimetric assays register their presence weakly. Identifying which specific molecules drive the activity requires chemical characterisation at the compound level, and this is where the team turned to instrumental analysis.

Gas chromatography coupled with mass spectrometry, or GC–MS, was used to profile the volatile and semi-volatile constituents of the extracts, revealing a suite of major bioactive compounds characteristic of halophyte chemistry. To prioritise candidates for drug development, the researchers then turned to molecular docking, a computational technique that predicts how tightly a small molecule fits into the binding pocket of a disease-relevant protein. Two inflammatory protein structures, deposited in the Protein Data Bank under the identifiers 1IK3 and 5IKR, served as the molecular targets. Among the identified phytochemicals, 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione showed the strongest binding affinities, at minus 7.1 and minus 7.0 kilocalories per mole for the two targets respectively. Binding energies in this range suggest meaningful intermolecular contacts such as hydrogen bonding and hydrophobic packing, which in docking studies are typically taken as an encouraging, though preliminary, sign of inhibitory potential.

The team also ran the lead compounds through SwissADME, a widely used web platform that estimates whether a molecule behaves like a plausible oral drug. The analysis indicated favourable drug-like properties, including profiles consistent with reasonable absorption, distribution and metabolic behaviour under the standard Lipinski-style criteria used in early drug discovery. No docking study or ADME prediction can replace experimental pharmacology, but together they act as a molecular sieve, filtering dozens of crude extract constituents down to a shortlist of compounds worth the expense of isolation, synthesis and biological testing.

The authors are careful to frame the work as an early-stage screening effort rather than a therapeutic claim. All of the antioxidant and anti-inflammatory data come from in vitro assays, and the docking results are computational predictions; the study itself concludes that the halophytes, particularly their hexane extracts, warrant further in vitro and in vivo investigation. That pipeline matters: many plant extracts that shine in a test tube fail when confronted with living systems, where issues of bioavailability, metabolism, toxicity and target specificity intervene. Nevertheless, the convergence of strong assay results, identifiable bioactive compounds, encouraging docking scores and favourable drug-likeness predictions is exactly the combination that natural products chemists look for when deciding which species to pursue.

Beyond the laboratory, the study carries an ecological and economic message. Coastal salt marshes are often treated as wastelands, reclaimed for aquaculture, industry or development, yet they harbour species with demonstrated pharmaceutical value and play vital roles in shoreline protection and nutrient cycling. Work of this kind strengthens the case for conserving these habitats, both for their ecosystem services and as living libraries of chemical diversity. If subsequent animal studies and, eventually, clinical research confirm the promise suggested by the Cuddalore samples, the humble marsh plants swaying at the edge of the Bay of Bengal may find a second career as sources of next-generation anti-inflammatory medicines.

Subject of Research: Antioxidant and anti-inflammatory bioactive compounds in coastal halophyte plants

Article Title: Assessment of antioxidant and anti-inflammatory effects of Suaeda maritima and Sesuvium portulacastrum collected from Cuddalore coast region

Article References: Baskaran, G., Natesan, M., Palanisamy, B. M., Mathiyazhagan, S., & Raji, S. (2026). Assessment of antioxidant and anti-inflammatory effects of Suaeda maritima and Sesuvium portulacastrum collected from Cuddalore coast region. Plant Biosystems, 160(5), Article 254. https://doi.org/10.1007/s44473-026-00266-7

Image Credits: AI Generated

DOI: 10.1007/s44473-026-00266-7

Keywords: halophytes, Suaeda maritima, Sesuvium portulacastrum, antioxidant activity, anti-inflammatory, phytochemistry, molecular docking, GC-MS, SwissADME, salt marsh, natural products, Cuddalore coast