Abstract
Objectives
This work aimed to isolate and characterize the chemical constituents of the roots of Pinus massoniana Lamb. and to evaluate their anti-inflammatory activity by assessing the inhibition of nitric oxide release in LPS-induced macrophages.
Methods
The compounds were isolated after extensive separation and purification. Structural elucidation of the new compound was performed using a combination of NMR spectroscopy, experimental circular dichroism (CD) spectroscopy, and computational CD analysis, whereas known compounds were identified by comparing their spectroscopic data with those reported in the literature. All compounds were evaluated for nitric oxide inhibition using the Griess assay.
Results
One new compound, namely pinumin A (
Conclusion
One new compound, namely pinumin A (
Introduction
Chronic inflammation plays a role in the pathogenesis of a wide range of chronic diseases, such as Alzheimer's disease, cardiovascular disorders, and so on. 1 This persistent, low-grade inflammation promotes tissue damage and disease progression through the sustained release of harmful mediators like pro-inflammatory reactive oxygen species, cytokines and chemokines. Critically, its pathological overproduction of nitric oxide (NO) during chronic inflammation exerts significant detrimental effects. This pathological level of NO can cause DNA damage, inhibit protein function, induce mitochondrial dysfunction, and reactions with other reactive molecules to form more destructive reactive nitrogen species (RNS), such as peroxynitrite anions (ONOO⁻). These mechanisms exacerbate oxidative stress and tissue injury, profoundly participating in the pathophysiology of chronic diseases.2,3
Natural products are important for drug research and development because of their complex and diverse molecular structures. 4 Pinus massoniana Lamb. (Pinaceae) is an important tree species in China, and its different parts are rich in a variety of bioactive constituents. Its nodes, 5 root bark, 6 branches,7–10 needles,11,12 and pollen13,14 were phytochemically investigated. These works report diterpenoids,5–7 triterpenoids, 8 procyanidins,9,10 flavonoids, 11 polysaccharides, 12 phenylmethanoids, 15 and phenylpropanoids 13 as main metabolites.
The root of P. massoniana, commonly known as “Song geng” in Mandarin is native to numerous provinces across southern China. In folk medicinal material, it is used as a rheumatid-relieving, for detoxification and to treat falls and injuries. Furthermore, the roots of P. massoniana serve as the natural and essential substrate for Poria cocos, a key medicinal and edible fungus. The development of the Poria sclerotium is entirely dependent on nutrients absorbed from the pine root. This sclerotium is then directly processed into various traditional Chinese functional foods, such as Fuling biscuits and soups. Therefore, the pine root demonstrates its dietary importance indirectly but fundamentally by being the primary material foundation for this widely consumed food-medicine. 14
Diterpenoids from P. massoniana significantly suppressed lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) overproduction in macrophages.
7
Additionally, pine pollen demonstrated multi-target anti-inflammatory effects by directly inhibiting the production of inflammatory mediators and modulating key signaling pathways to regulate inflammation-related gene expression.
16
Therefore, a systematic investigation into the chemical constituents and bioactivities of P. massoniana might be of value for identifying novel NO inhibitors.
6
The roots were phytochemically investigated once, with the study focusing on the root bark.
6
Herein, we report the first comprehensive investigation of the entire root. In this work, a total of fourteen compounds were isolated from the ethyl acetate extract of the roots of P. massoniana. They include one new (
Materials and Methods
General Experimental Procedures
The key data for structure elucidation were collected on the following instruments: optical rotations on a Horiba SEPA-300 polarimeter; UV, IR (KBr pellets), and NMR (1H, 13C, 2D) spectra were acquired on a Shimadzu UV-2401PC spectrophotometer, a Bruker Tensor 27 spectrometer, and a Bruker DRX-500 spectrometer, respectively. High-resolution mass spectrometry was conducted using an Applied Biosystems Mariner 5140 instrument.
To isolate and purify the constituents, TLC and column chromatography were conducted on pre-coated silica gel GF254 plates and silica gel (200‒300 mesh; Qingdao Marine Chemical), respectively, while Sephadex LH-20 was also employed. Final purification was performed using a Sep Sciences MH-LC52 medium-high pressure preparative liquid chromatography system (Sep Sciences, Beijing, China, Thermo column, 5 μm, 10 × 250 mm). All solvents met or exceeded the purity of analytical grade (≥95%).
Plant Material
The roots of Pinus massoniana Lamb. were collected from Mountain Dong ‘an County, Hunan Province, China, on July 15, 2024. The species was identified by Prof. X. J. Zhou from a specimen of the whole plant. A corresponding voucher sample (ZXJ-0157) is kept in the research laboratory at Hunan University of Chinese Medicine for future reference.
Extraction and Isolation
Extraction of the plant material (6.0 kg dried roots of P. massoniana) was performed using 60% aqueous ethanolic solvent (2 × 24 L). The next step was to concentrate the extract under reduced pressure. The material was then successively extracted with petroleum ether and EtOAc (6 × 4.0 L for each solvent). The petroleum ether extract showed no significant inhibitory activity against LPS-induced NO production in preliminary screening and was therefore not subjected to further phytochemical investigation.
Column chromatographic separation of the EtOAc extract (78.5 g) over silica gel employing a gradient of petroleum ether/EtOAc (15:1, 5:1, 3:1, 1:1, 1:2, 1:4) gave eight fractions (Frs. 1-8). Four subfractions (Frs. 4-1 to 4-4) were obtained from Fr. 4 (3.43 g) by Sephadex LH-20 column chromatography (MeOH). Frs. 4-4 (660 mg) was separated using a medium and high-pressure preparation liquid phase system (MH-LC), eluting with 60% aqueous MeOH to give compound
No other secondary metabolites were found in sufficient amount or purity to be characterized in the other subfractions of the EtOAc extract.
Pinumin A (
1H (600 MHz) and 13C NMR (151 MHz) Spectroscopic Data of 1 in CD3OD.
ECD Calculation
We used Sybyl-X 2.0 to sample the conformations and used the MMFF94S force field (energy cutoff value: 5 kcal/mol) to obtain nine low-energy conformations. These structures were optimized and frequencies calculated in ORCA 5.0.1. using the B3LYP-D3(BJ)/6-31G* method and CPCM (methanol solvent) 17 confirming that they are all local minima (no imaginary frequencies). Then, TD-DFT calculations were performed using the PBE0/def2-TZVP method in CPCM (methanol solvent) 18 and the excitation energies, oscillator strengths, and rotatory strengths for the sixty lowest-energy-excited states were calculated. The ECD spectrum was simulated using a Gaussian function (σ = 0.30). 19 The Gibbs free energy of the conformation was calculated from the thermal correction of B3LYP-D3(BJ)/6-31G and the electron energy of wB97M-V/def2-TZVP. Finally, the Boltzmann-weighed spectrum was simulated based on the relative ΔG values and compared with experimental data applied to the configurational assignment of the chiral center.
Biological Assays
A density of 105 cells/mL was used to seed RAW 264.7 cells (Cangsha, Abiowell, China) in 96-well plates. Then, the cells were subjected to a 24-h culture period at 37 °C within a 5% CO₂ incubator. To evaluate anti-inflammatory activity, cells were first primed with the compounds for 1 h after the initial 24 h culture, followed by LPS (1 μg/mL) challenge for 24 h. The inhibitory effect on NO generation was determined by measuring absorbance at 540 nm using the Griess reagent. A series of standard solutions were prepared with NaNO2 as the standard to draw the standard curve. Based on the measured absorbance values, the corresponding nitrite concentration was determined, from which the inhibition rate of NO release was calculated. The positive control was dexamethasone, while cell viability was determined by the CCK-8 method. All experiments were independently performed five times, and the data are expressed as the mean ± SD. Statistical significance was determined using a student's t-test, with a p-value of ≤ 0.05 considered significant.
Results and Discussion
Compound

Key COSY (bold) and HMBC (arrows) correlations for compound 1.

Experimental and calculated ECD spectra of 1.
The known compounds were identified as cedrusinin (

Skeletal (shorthand) structures of the isolated compounds (1-14).
As the roots of P. massoniana are used in the treatment of conditions related to chronic inflammation such as rheumatic swelling and pain, the isolated compounds were tested for LPS-induced NO production in RAW 264.7 cells using the Griess method. Dexamethasone was used as a positive control. At a concentration of 100 μM, compounds
However, this study has several limitations. The anti-inflammatory activity was evaluated only in an LPS-induced RAW 264.7 macrophage model, focusing on NO suppression without elucidating the underlying mechanism. Therefore, a deeper understanding of their mechanisms, selectivity, and in vivo efficacy is required before their therapeutic potential can be pursued, necessitating future work on comprehensive pharmacokinetic profiling, toxicity assessment, and structure optimization. (Table 2) (Figure 4).

Inhibitory curves of compounds 1, 5 and 8 on LPS-induced NO production in RAW 264.7 cells.
Inhibition of NO Production in LPS-Induced RAW 264.7 Cells by Compounds 1, 5, and 8.
Data are mean IC₅₀ [95% CI] (SD of IC₅₀ values, n = 5), derived from four-parameter logistic (4PL) curve fits of five independent replicates, the overall mean and CI were calculated using a t-distribution model.
Conclusion
In this study, one new compound, namely pinumin A, and thirteen known compounds were isolated from the roots of P. massoniana. Compounds
Supplemental Material
sj-doc-1-npx-10.1177_1934578X261433098 - Supplemental material for Pinumin A, a Stilbenoid from the Roots of Pinus massoniana with Nitric Oxide Inhibitory Effect
Supplemental material, sj-doc-1-npx-10.1177_1934578X261433098 for Pinumin A, a Stilbenoid from the Roots of Pinus massoniana with Nitric Oxide Inhibitory Effect by Hongyu Jiang, Yuxin Peng, Guangyun Su, Xining Sun, Xuejing Li and Xiaojiang Zhou in Natural Product Communications
Footnotes
Acknowledgments
This work was supported by Science and Medicine Joint Fund of Hunan Provincial National Natural Science Foundation, China (No. 2024JJ8160).
Ethical Statement
This study did not involve any human participants, human data, animal experiments, or animal tissues. The research solely focused on the phytochemical investigation of plant material (Pinus massoniana). Therefore, ethical approval from an institutional review board or ethics committee was not required for this work.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Medicine Joint Fund of Hunan Provincial National Natural Science Foundation, (grant number 2024JJ8160).
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Supplemental Material
Supplementary data (NMR spectra and HRESIMS) for compound
References
Supplementary Material
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