Justicia procumbens leaves and flowers curb gut inflammation while higher nutrient strength boosts lignan yields

Justicia procumbens, a medicinal herb long used across Korea, China, India, and Southeast Asia for fever, cough, and inflammatory complaints, has now been mapped organ by organ in the laboratory. Researchers report that extracts of its leaves and flowers strongly damp an inflammatory signal in human intestinal cells, while stems and roots do the job only weakly. The same study then asked a practical question: can growers coax more of the plant’s signature anti-inflammatory lignans out of the harvestable aerial biomass simply by adjusting the strength of the nutrient solution? The answer, under the conditions tested, was yes.

The work, published in Applied Biological Chemistry, centered on HT-29 human colorectal epithelial cells, a standard laboratory model that responds to the inflammatory cytokine interleukin-1 beta by secreting interleukin-8, or IL-8, a chemokine that recruits immune cells. When the researchers stimulated these cells with IL-1 beta at 1 nanogram per milliliter for five hours, IL-8 production rose markedly above untreated controls. Treating the cells beforehand with an extract of J. procumbens aerial parts, or with the purified lignans justicidin A and justicidin B, brought that IL-8 surge down at concentrations chosen to be non-cytotoxic. Cell viability assays confirmed the effect was not an artifact of dying cells.

Justicidin B generally showed a stronger inhibitory response than justicidin A under the tested conditions, and the whole aerial-part extract also produced pronounced IL-8 inhibition. The authors are careful about what this means. Because plant extracts contain many compounds, they write that justicidin A and B should be viewed as representative bioactivity-associated constituents rather than the sole drivers of the extract’s effect. Notably, justicidin A has previously been reported to suppress NF-kappa-B activity in HT-29 cells, a signaling pathway central to inflammatory gene expression, which lends mechanistic plausibility to the marker-based interpretation.

The organ-level comparison sharpened the picture. Plants grown hydroponically were separated into leaves, stems, flowers, and roots, with samples pooled from three plants and analyzed in triplicate. Leaf and flower extracts showed pronounced inhibition of IL-1 beta-induced IL-8 production, the stem extract showed a weaker but detectable response, and the root extract was the least active. In other words, the anti-inflammatory activity tracked the aerial organs, the very tissues that make up the harvestable crop, rather than the belowground parts.

Chemical profiling by high-performance liquid chromatography then connected that activity pattern to the distribution of the two marker lignans. Justicidin A was quantified in all organs and reached its highest levels in flowers, followed by leaves, with lower amounts in stems and roots. Justicidin B was most abundant in flowers and also plentiful in leaves, while signals in stems and roots fell below the limit of quantification. The parallel between where the lignans concentrate and where the IL-8 inhibition is strongest supports their use as bioactivity-associated markers, though the authors stress that other phytochemicals in the extracts may contribute and that the correspondence does not prove the two lignans alone cause the effect.

With leaves and flowers identified as the functionally relevant organs, and both being components of the cuttable aerial biomass, the team selected aerial parts as the practical production unit and turned to cultivation. Seedlings raised in a plant factory under LED lighting were transplanted to an autumn greenhouse and grown in hydroponic trays at two nutrient-solution electrical conductivity levels, 1.2 and 2.0 decisiemens per meter, with three replicate trays of ten plants per treatment. Plants were harvested weekly from 7 to 42 days after transplanting, and each harvest was separated into aerial parts and roots for growth, physiological, and lignan measurements.

Growth responded to the higher EC in a patterned way. Aerial-part fresh weight was significantly greater at EC 2.0 at 35 and 42 days after transplanting, while aerial-part dry weight differed little between treatments at most harvest times, and plant height and water content were not significantly affected. Root growth was more sensitive: root fresh weight was significantly higher at EC 2.0 at 21, 28, and 35 days, and root dry weight was elevated at several harvests, so root-to-aerial-part ratios were generally higher under the stronger solution, particularly later in cultivation. Electrolyte leakage, a common indicator of stress-related membrane injury, did not differ between treatments at the final harvest, suggesting the higher EC did not impose marked physiological damage.

Chlorophyll told a time-dependent story. Total chlorophyll content differed significantly between treatments at 14, 35, and 42 days after transplanting, with EC 1.2 ahead at day 14 but EC 2.0 ahead at days 35 and 42, and no differences at 7, 21, or 28 days. The authors suggest the later advantage at EC 2.0 may reflect sufficient nutrient availability to sustain chlorophyll maintenance, while noting that the transient early difference shows the response varies with harvest time.

The lignan yields, calculated by multiplying each compound’s concentration by aerial-part dry weight, generally climbed with harvest time under both EC levels, but the higher EC pushed them further. Justicidin A yield per plant was significantly higher at EC 2.0 at 7, 35, and 42 days after transplanting, with the largest values at the final harvest. Justicidin B showed a later response, significantly higher at EC 2.0 at 21, 28, 35, and 42 days. Because yield integrates both biomass and compound concentration, the authors interpret these gains as the combined outcome of growth and lignan accumulation under a physiologically tolerable condition rather than a stress response.

Limitations frame the promise. Only two EC levels were tested in a single autumn season, so the results do not define an optimal conductivity, and the authors call for broader EC ranges, seasonal replication, and harvest-time optimization. Even so, the study links three layers that rarely appear together in one paper: cell-based functional activity, organ-specific chemistry, and cultivation management. For a plant whose traditional anti-inflammatory reputation is now measurable in gut epithelial cells, the practical takeaway is that the aerial harvest, rich in the right organs and the right lignans, can be made more productive by tuning the nutrient solution, a step toward reproducible functional-material production rather than reliance on variable wild harvests.

Subject of Research: Organ-specific intestinal anti-inflammatory activity of Justicia procumbens and electrical-conductivity-dependent lignan productivity in hydroponically grown aerial parts

Article Title: Organ-specific intestinal anti-inflammatory activity in Justicia procumbens and EC-dependent lignan productivity in aerial parts

Article References: Kim, Y. L., Choi, Y. B., Truong, T. Q., Huynh, P. K., Kim, M. D., Bae, W.-Y., Kang, K., Lee, H. J., Ahn, T. I., & Kim, S. M. (2026). Organ-specific intestinal anti-inflammatory activity in Justicia procumbens and EC-dependent lignan productivity in aerial parts. Applied Biological Chemistry, 69(1), Article 83. https://doi.org/10.1186/s13765-026-01147-5

Image Credits: AI Generated

DOI: 10.1186/s13765-026-01147-5

Keywords: Justicia procumbens, justicidin A, justicidin B, HT-29 cells, IL-8, anti-inflammatory, hydroponics, electrical conductivity, lignans, aerial parts, chlorophyll content, electrolyte leakage