Sitoindoside X

Sitoindoside X at a Glance

Sitoindoside X is a glycowithanolide — a withanolide steroidal lactone carrying a sugar — found in the root of ashwagandha (Withania somnifera). It was isolated and named in 1989 together with its close sibling sitoindoside IX, and the two have been treated as a pair ever since ^{1Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →}.

What makes sitoindoside X its own molecule is a structural detail: on top of the glucose that defines the glycowithanolides, it carries a long-chain fatty-acyl (palmitoyl) ester, making it an acylsteryl glucoside (molecular formula C₅₀H₇₈O₁₂) ^{7Reference 7National Center for Biotechnology Inform · 2026PubChem Compound Summary for Sitoindoside X (CID 189702) and Sitoindoside IX (CID 189586)View study →}. Sitoindoside IX, by contrast, is the plain, non-acylated glucoside — 27-O-β-D-glucopyranosylwithaferin A (C₃₄H₄₈O₁₁) ^{7Reference 7National Center for Biotechnology Inform · 2026PubChem Compound Summary for Sitoindoside X (CID 189702) and Sitoindoside IX (CID 189586)View study →}. In that respect sitoindoside X is chemically closer to the earlier acylsterylglucoside sitoindosides VII and VIII than IX is ^{6Reference 6Bhattacharya SK et al. · 1987Anti-stress activity of sitoindosides VII and VIII, new acylsterylglucosides from Withania somniferaView study →}.

Honesty first: almost no evidence exists for sitoindoside X as an individual molecule. Nearly everything below comes from studies of the sitoindoside IX + X pair or of the whole Withania somnifera glycowithanolide (WSG) fraction — an equimolar mix of sitoindosides VII–X plus withaferin A. Read every claim as fraction-level, animal-model data, not proof of what the pure compound does in people. For the shared pharmacology in full, see the companion page on sitoindoside IX; the focus here stays on sitoindoside X specifically.

What Distinguishes Sitoindoside X

The sitoindosides are a numbered series of glycosylated withanolides from Withania somnifera. Sitoindosides VII and VIII (reported in 1987) are acylsterylglucosides; sitoindosides IX and X (reported in 1989) were introduced as “two new glycowithanolides” ^{1,6Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 6Bhattacharya SK et al. · 1987Anti-stress activity of sitoindosides VII and VIII, new acylsterylglucosides from Withania somniferaView study →}.

Within that pairing, the practical difference between the siblings is the acyl group:

• Sitoindoside IX — a straightforward glucoside of the withanolide aglycone (27-O-β-D-glucopyranosylwithaferin A), C₃₄H₄₈O₁₁, MW ≈ 633 ^{7Reference 7National Center for Biotechnology Inform · 2026PubChem Compound Summary for Sitoindoside X (CID 189702) and Sitoindoside IX (CID 189586)View study →}.
• Sitoindoside X — the same glycowithanolide skeleton bearing an additional palmitoyl (hexadecanoate) ester on the sugar, C₅₀H₇₈O₁₂, MW ≈ 871 ^{7Reference 7National Center for Biotechnology Inform · 2026PubChem Compound Summary for Sitoindoside X (CID 189702) and Sitoindoside IX (CID 189586)View study →}. That extra ~238-mass-unit fatty-acid chain is the entire structural gap between the two, and it makes sitoindoside X markedly more lipophilic than IX.

This is the only property for which sitoindoside X is clearly individuated in the literature. Its biology has never been separated from sitoindoside IX or from the wider fraction — so the sections below describe shared, pair-or-fraction pharmacology, flagged as such.

What It's Used For

The evidence is entirely preclinical (rodent) and, for the parts that name sitoindoside X at all, comes from a single 1989 report on the IX + X pair; the rest is the WSG fraction ^{1,2,3,4,5Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →Reference 3Bhattacharya SK et al. · 1995AnimalEffects of glycowithanolides from Withania somnifera on an animal model of Alzheimer’s disease and perturbed central cholinergic markers of cognition in ratsView study →Reference 4Bhattacharya SK et al. · 2000Anxiolytic-antidepressant activity of Withania somnifera glycowithanolides: an experimental studyView study →Reference 5Bhattacharya A et al. · 2001AnimalAnti-oxidant effect of Withania somnifera glycowithanolides in chronic footshock stress-induced perturbations of oxidative free radical scavenging enzymes and lipid peroxidation in rat frontal cortex and striatumView study →}. Take the following as a description of what the glycowithanolide fraction does, with sitoindoside X as one contributor.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Every score here is capped low: the data are rodent-only and almost always the IX + X pair or the whole glycowithanolide fraction, not sitoindoside X isolated.

01Anti-Stress / AdaptogenicShaky30%1989 study testing sitoindosides IX & X directly (rodent) ^{1Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →}

02Antioxidant (Brain Enzymes)Shaky28%Replicated rodent data on the WSG fraction ^{2,5Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →Reference 5Bhattacharya A et al. · 2001AnimalAnti-oxidant effect of Withania somnifera glycowithanolides in chronic footshock stress-induced perturbations of oxidative free radical scavenging enzymes and lipid peroxidation in rat frontal cortex and striatumView study →}

03Immunomodulatory (Macrophage)Shaky22%1989 study — IX & X mobilized/activated macrophages (rodent) ^{1Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →}

04Anti-Amnesic / CognitionShaky18%WSG fraction on cholinergic cognition markers + aged-rat memory (rodent) ^{1,3Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 3Bhattacharya SK et al. · 1995AnimalEffects of glycowithanolides from Withania somnifera on an animal model of Alzheimer’s disease and perturbed central cholinergic markers of cognition in ratsView study →}

Mechanisms

Every row is rodent data on the sitoindoside IX + X pair or the whole glycowithanolide fraction. No mechanism has been demonstrated for sitoindoside X in isolation.

Pharmacokinetics

Essentially uncharacterized. No absorption, bioavailability, metabolism or half-life data exist for sitoindoside X specifically — or, in practice, for the isolated glycowithanolides at all. Two structural features would be expected to matter: it is a glucoside (dietary glycosides are commonly hydrolyzed by gut and microbial enzymes, so the circulating species after oral intake may be a deglycosylated aglycone rather than the intact molecule), and it carries a palmitoyl fatty-acid ester that makes it considerably more lipophilic than sitoindoside IX. How those competing properties net out for oral absorption has not been measured. This unknown pharmacokinetics is a real limit on reading anything into the rodent tissue results.

Clinical Trials

There are no clinical trials of sitoindoside X — neither as an isolated compound nor as a defined IX + X preparation. Human evidence for ashwagandha uses standardized whole-root extracts standardized to total withanolide content, within which sitoindoside X is at most a trace constituent.

Last checked: July 2026.

Isolate vs. Plant Studies

This molecule sits at the far plant/fraction end of the spectrum. There is no study of purified sitoindoside X on its own. The closest thing to isolate data is the 1989 report, which tested sitoindosides IX and X as a named pair ^{1Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →}; everything else — antioxidant, anxiolytic-antidepressant, anti-Alzheimer’s — used the equimolar Withania somnifera glycowithanolide fraction (sitoindosides VII–X + withaferin A) ^{2,3,4,5Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →Reference 3Bhattacharya SK et al. · 1995AnimalEffects of glycowithanolides from Withania somnifera on an animal model of Alzheimer’s disease and perturbed central cholinergic markers of cognition in ratsView study →Reference 4Bhattacharya SK et al. · 2000Anxiolytic-antidepressant activity of Withania somnifera glycowithanolides: an experimental studyView study →Reference 5Bhattacharya A et al. · 2001AnimalAnti-oxidant effect of Withania somnifera glycowithanolides in chronic footshock stress-induced perturbations of oxidative free radical scavenging enzymes and lipid peroxidation in rat frontal cortex and striatumView study →}. Human ashwagandha trials, in turn, use standardized whole root extract, where the effect cannot be attributed to any single glycowithanolide. So for sitoindoside X the usual caveat is at its strongest: the molecule is a plausible contributor to ashwagandha’s adaptogenic/antioxidant activity, but its individual role has never been isolated, and transferability from fraction to molecule to human is entirely unproven.

Its Role in Plants

In Withania somnifera, the glycowithanolides are glycosylated (and, for sitoindoside X, fatty-acylated) derivatives of the withanolide steroidal lactones. Glycosylation and acylation of steroidal defence metabolites is a common plant strategy — it changes solubility, storage and mobility relative to the free aglycone (here, a withaferin-A-type withanolide). The withanolides themselves are part of the Solanaceae chemical-defence repertoire; the sitoindosides are best understood as modified, sugar-bearing members of that class rather than as separately characterized ecological signals. Detailed biosynthesis of the individual sitoindosides has not been worked out.

Prevalence in Nature

Sitoindoside X is a minor constituent of ashwagandha (Withania somnifera) root and, like the other sitoindosides, is a signature of this plant rather than a widely distributed phytochemical. Its abundance has not been quantified in the literature — it is described qualitatively as part of the small anti-stress glycowithanolide fraction, not as a bulk component. Commercial ashwagandha extracts are standardized to total withanolides, so any sitoindoside X present travels as a trace member of that pool rather than being measured on its own.

Discovery & Synthesis

Sitoindoside X was first isolated and named in 1989 by Shibnath Ghosal and co-workers, reported together with sitoindoside IX as “two new glycowithanolides from Withania somnifera” in Phytotherapy Research; the same paper described their immunomodulatory (macrophage-activating), anti-stress and CNS/cognitive effects ^{1Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →}. The name follows the “sitoindoside” series Ghosal’s group had been building for Withania’s acylsteryl glucosides and glycowithanolides, of which the anti-stress sitoindosides VII and VIII (1987) were earlier members ^{6Reference 6Bhattacharya SK et al. · 1987Anti-stress activity of sitoindosides VII and VIII, new acylsterylglucosides from Withania somniferaView study →}.

Total synthesis of sitoindoside X is not documented — as with most withanolide glycosides, the molecule is obtained by extraction from ashwagandha root, not by synthesis, and it has no standalone commercial production separate from whole-extract manufacture.

Patents: not yet researched.

Toxicity & Safety

Sitoindoside X carries a low flag. It is a glycowithanolide from the anti-stress fraction of ashwagandha root — the gentle, adaptogenic end of Withania’s chemistry — and, unlike the aglycone-type withanolide withaferin A (which is flagged moderate for its cytotoxicity), the sitoindosides have only ever been reported in benign anti-stress, antioxidant and immunomodulatory contexts, with no toxicity signal in the rodent work ^{1,2Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →}. The important honesty is that this “low” reflects an absence of adverse findings, not a dedicated safety dataset: there is no isolated-molecule toxicology, no genotoxicity or reproductive-toxicity study, and no human safety data for sitoindoside X.

Safety at a Glance

✅ Low / no toxicity

• Belongs to ashwagandha’s benign anti-stress fraction. The rodent glycowithanolide studies report adaptogenic, antioxidant and immune effects with no toxicity signal ^{1,2Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →}.
• Not the cytotoxic withanolide. Unlike the withaferin-A aglycone, sitoindoside X is a glycoside from the well-tolerated adaptogenic fraction.
• No dedicated safety data. No isolate toxicology, genotoxicity, reproductive or human safety studies exist — “low” means no red flags found, not a clean bill proven.
• Pregnancy/lactation is decided at the herb level. Ashwagandha itself carries pregnancy cautions; those belong on the herb and product pages, not to this trace molecule.

Dosage

There is no established human dose for sitoindoside X, and it has never been administered to people as an isolated compound. The rodent studies dosed either the sitoindoside IX + X pair or the whole glycowithanolide fraction, not the pure molecule, so even the animal dosing does not isolate its contribution ^{1,2,4Reference 1Ghosal S et al. · 1989Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somniferaView study →Reference 2Bhattacharya SK et al. · 1997Antioxidant activity of glycowithanolides from Withania somniferaView study →Reference 4Bhattacharya SK et al. · 2000Anxiolytic-antidepressant activity of Withania somnifera glycowithanolides: an experimental studyView study →}. In practice, the only human exposure is indirect — sitoindoside X is a trace glycowithanolide within standardized ashwagandha root extract, which is dosed on total withanolide content rather than on any individual sitoindoside. Any figures here would be doses studied in animal research on the fraction, not a personal recommendation.

References

1. Ghosal S, Lal J, Srivastava R, Bhattacharya SK, Upadhyay SN, Jaiswal AK, Chattopadhyay U (1989). Immunomodulatory and CNS effects of sitoindosides IX and X, two new glycowithanolides from Withania somnifera. Phytotherapy Research, 3(5), 201–206. https://doi.org/10.1002/ptr.2650030510
2. Bhattacharya SK, Satyan KS, Ghosal S (1997). Antioxidant activity of glycowithanolides from Withania somnifera. Indian Journal of Experimental Biology, 35(3), 236–239. https://pubmed.ncbi.nlm.nih.gov/9332168/
3. Bhattacharya SK, Kumar A, Ghosal S (1995). Effects of glycowithanolides from Withania somnifera on an animal model of Alzheimer’s disease and perturbed central cholinergic markers of cognition in rats. Phytotherapy Research, 9(2), 110–113. https://doi.org/10.1002/ptr.2650090206
4. Bhattacharya SK, Bhattacharya A, Sairam K, Ghosal S (2000). Anxiolytic-antidepressant activity of Withania somnifera glycowithanolides: an experimental study. Phytomedicine, 7(6), 463–469. https://pubmed.ncbi.nlm.nih.gov/11194174/
5. Bhattacharya A, Ghosal S, Bhattacharya SK (2001). Anti-oxidant effect of Withania somnifera glycowithanolides in chronic footshock stress-induced perturbations of oxidative free radical scavenging enzymes and lipid peroxidation in rat frontal cortex and striatum. Journal of Ethnopharmacology, 74(1), 1–6. https://pubmed.ncbi.nlm.nih.gov/11137343/
6. Bhattacharya SK, Goel RK, Kaur R, Ghosal S (1987). Anti-stress activity of sitoindosides VII and VIII, new acylsterylglucosides from Withania somnifera. Phytotherapy Research, 1(1), 32–37. https://doi.org/10.1002/ptr.2650010108
7. National Center for Biotechnology Information (2026). PubChem Compound Summary for Sitoindoside X (CID 189702) and Sitoindoside IX (CID 189586). PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/189702

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