Skip to content
Last night, I told you about a discovery in Brazil that surprised the scientific community. Researchers found CBD—cannabidiol—in a common South American shrub called Trema micrantha. A plant that isn’t cannabis. A plant that grows wild across Brazil like a weed.
The discovery made headlines. Legal alternatives to cannabis. New CBD sources for countries with restrictive regulations. A botanical workaround for hemp prohibition.
Exciting stuff, especially for the convergent evolution angle—nature making the same compound in completely unrelated plant species, separated by millions of years.
But while everyone was focused on Brazil’s preliminary findings, a more significant study sat quietly in a peer-reviewed journal, published two years earlier.
Thailand. 2021. Same plant genus. Same cannabinoids.
But the Thai researchers didn’t stop at chemical analysis.
They tested the extracts against multidrug-resistant bacteria. And they worked.
This is the story nobody talked about.
The Thailand Study: What They Actually Did
A team of researchers from multiple Thai universities—Thammasat University, Pibulsongkram Rajabhat University, and Silpakorn University—collaborated on a comprehensive study of Trema orientalis.
Same genus as the Brazilian discovery. Different species. Closely related to cannabis through phylogenetic analysis.
Trema orientalis grows throughout tropical Asia. Common pioneer species—one of the first plants to colonize disturbed soil. Shows up uninvited in agricultural areas, forest edges, and beach forests.
The researchers collected nine specimens from three distinct floristic regions in Thailand:
Northern Thailand: Agricultural areas and forest edges in Uttaradit, Phitsanulok, and Phetchabun provinces.
Southeastern Thailand: Beach forests in Chanthaburi, Rayong, and Trat provinces along the coast.
Southern (Peninsular) Thailand: Agricultural and disturbed areas in Chumphon, Nakhon Si Thammarat, and Songkhla provinces.
They specifically collected mature inflorescences—the flowers—during the flowering period from November 2019 to February 2020.
Why flowers? Because in the cannabis family (Cannabaceae), cannabinoids concentrate in the flower structures, particularly in trichomes on the surface.
The methodology was rigorous. Air-dried without sunlight. Ground into powder. Macerated in methanol for 10 days. Extracted and partitioned into hydrophilic and lipophilic fractions. The lipophilic fraction was further separated using column chromatography with gradient elution.
Then analyzed with gas chromatography-mass spectrometry (GC-MS) using internal cannabinoid standards for precise identification.
This wasn’t casual exploration. This was systematic, reproducible, scientifically rigorous analysis.
Published in PeerJ, a respected peer-reviewed journal, in May 2021.
And here’s what they found.
The Cannabinoid Profile: CBN Takes the Lead
All nine specimens, across all three regions, contained cannabinoids.
THC (tetrahydrocannabinol), CBD (cannabidiol), and CBN (cannabinol) appeared in varying concentrations depending on geographic location and growing conditions.
But one cannabinoid dominated: CBN.
Northern Thailand samples:
- CBN: up to 357.46 mg/kg
- THC: up to 89.96 mg/kg
- CBD: not detected
Southeastern Thailand samples (coastal):
- CBN: 50-55 mg/kg
- THC: not detected
- CBD: not detected
Southern Thailand samples:
- CBN: up to 140.19 mg/kg
- THC: up to 38.13 mg/kg
- CBD: up to 5.22 mg/kg
This is unusual.
In cannabis, CBN is typically a minor cannabinoid. It forms when THC degrades through oxidation or aging. You find elevated CBN in old cannabis, stored products, material exposed to light and air.
But in Trema orientalis, CBN appears to be the primary cannabinoid the plant actively produces.
Not a degradation product. A deliberate biosynthetic output.
Why would the plant prioritize CBN over CBD or THC?
The answer became clear when they tested antibacterial activity.
Testing Against Superbugs: The Part Everyone Missed
The Thai researchers obtained four bacterial strains from the Department of Medical Science, Ministry of Public Health, Thailand.
Not random bacteria. WHO priority pathogens—the multidrug-resistant superbugs that cause serious infections and resist standard antibiotics:
Staphylococcus aureus ATCC 43300: Methicillin-resistant (MRSA). One of the most notorious hospital-acquired infection agents. Causes skin infections, pneumonia, bloodstream infections, and surgical site infections. Resistant to beta-lactam antibiotics including methicillin, oxacillin, and amoxicillin.
Staphylococcus aureus ATCC 25923: Standard strain for comparison.
Pseudomonas aeruginosa ATCC 27853: Gram-negative bacteria that causes pneumonia, particularly in hospital settings and immunocompromised patients. Produces AmpC β-lactamase—an enzyme that breaks down antibiotics. Naturally resistant to many drug classes.
Acinetobacter baumannii ATCC 19606: Notorious for hospital-acquired infections. Causes pneumonia, bloodstream infections, wound infections, and meningitis. Extremely drug-resistant strains have emerged globally. Major problem in intensive care units.
These are the bacteria that make infectious disease doctors nervous. The ones developing resistance faster than we develop new antibiotics.
The researchers took the cannabinoid-containing fraction (labeled S3 in their study) and tested it using two methods:
Disk diffusion assay: Paper disks soaked in extract, placed on bacterial cultures. If the extract inhibits growth, a clear zone appears around the disk.
Broth microdilution assay: Serial dilutions to determine the minimum inhibitory concentration (MIC)—the lowest concentration that stops bacterial growth.
Both tests followed Clinical and Laboratory Standards Institute (CLSI) guidelines—the gold standard for antimicrobial susceptibility testing.
The results:
The cannabinoid fraction inhibited all four bacterial strains.
Clear zones of inhibition: 8 to 14 millimeters diameter.
MIC values:
- S. aureus ATCC 43300 (MRSA): 64.25 µg/mL
- S. aureus ATCC 25923: 31.25 µg/mL
- P. aeruginosa ATCC 27853: 31.25 µg/mL
- A. baumannii ATCC 19606: 31.25 µg/mL
For context, those concentrations are comparable to pharmaceutical antibiotics tested in the same study.
The northern Thailand samples—highest in CBN content—showed the strongest antibacterial activity across all bacterial strains.
Cannabinoids from Trema orientalis killed multidrug-resistant bacteria at clinically relevant concentrations.
And nobody talked about it.
Traditional Medicine: Validation Centuries in the Making
Here’s where the story gets interesting.
Trema orientalis has been used in traditional medicine throughout tropical Asia for centuries. Particularly in Thailand and surrounding regions.
The uses are well-documented in ethnobotanical literature:
Respiratory infections: Bronchitis, pneumonia, pleurisy—inflammation of the membrane surrounding the lungs.
Fever reduction: General antipyretic properties.
Infectious diseases: Bacterial and viral infections, particularly of the respiratory system.
The traditional preparation method: crush the inflorescences (flowers), extract the liquid, administer to patients—especially children—suffering from lung infections.
J.M. Watt and M.G. Breyer-Brandwijk documented this use in their 1962 reference work The Medicinal and Poisonous Plants of Southern and Eastern Africa. Traditional healers across the region used Trema species specifically for respiratory ailments involving infection.
Nobody understood the mechanism. The chemistry was unknown. The active compounds were unidentified.
But it worked. Consistently enough to be passed down through generations.
Now we know why.
The flowers contain cannabinoids.
Those cannabinoids kill respiratory bacteria.
The validation loop is complete.
Traditional medicine doesn’t need validation from peer-reviewed journals. It functioned effectively for centuries before anyone understood cannabinoid receptors, bacterial cell walls, or minimum inhibitory concentrations.
But when modern research confirms ancient knowledge—with reproducible results, documented methodology, published findings—it’s worth paying attention.
The Thai researchers tested their extracts specifically against bacteria that cause respiratory infections. Pseudomonas aeruginosa and Acinetobacter baumannii are major causes of hospital-acquired pneumonia.
The extracts inhibited both. At low concentrations.
Science just confirmed what traditional healers already knew.
CBN: The Antibacterial Cannabinoid
So which compound was doing the heavy lifting?
The cannabinoid profile of the most antibacterially active fraction (S3) showed:
Dominant compound: Cannabinol (CBN)
Present in all samples across all regions. Concentrations up to 357 mg/kg in northern Thailand specimens. Far exceeding THC or CBD content.
CBN doesn’t get much attention in mainstream cannabinoid discussions. CBD dominates wellness conversations. THC dominates legalization debates. CBN is the forgotten middle sibling.
But CBN has its own impressive pharmacological profile.
Sedative properties: CBN is known for promoting sleep. Aged cannabis—which has higher CBN due to THC degradation—often feels more sedating and relaxing than fresh material. CBN binds to cannabinoid receptors with different affinity than THC, producing calming effects without significant psychoactivity.
Anticonvulsant effects: Research shows CBN can reduce seizure activity. Not as potent as CBD for epilepsy, but demonstrates anticonvulsant properties nonetheless.
Antibacterial activity: This is where CBN shines. Multiple studies have documented CBN’s effectiveness against bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA).
A 2008 study by Appendino et al. published in the Journal of Natural Products tested five major cannabinoids against various MRSA strains. All five showed potent antibacterial activity, with MIC values comparable to or better than standard antibiotics.
CBN was particularly effective. It works by disrupting bacterial cell membranes, interfering with membrane potential and function. The bacteria can’t maintain cellular integrity, and they die.
Importantly, CBN showed activity against strains resistant to multiple antibiotic classes. When methicillin doesn’t work, when penicillin doesn’t work, when vancomycin struggles—CBN still inhibits growth.
The Thailand study confirms this. Their CBN-rich extracts from Trema orientalis inhibited MRSA at concentrations as low as 31.25 µg/mL.
Nature didn’t just make cannabinoids twice in unrelated plants.
It made the specific cannabinoid best suited for fighting the infections those plants face.
Why Plants Make Antimicrobial Compounds
Let’s think about Trema orientalis‘s growing environment.
Tropical Thailand. Near the equator in some regions. Coastal humidity in others. Agricultural disturbance. Forest edges.
The plant faces multiple environmental stressors:
High UV radiation: Tropical and near-equatorial locations receive intense ultraviolet light year-round. UV radiation damages DNA, proteins, and cellular structures. Plants need protection for their reproductive tissues—flowers and seeds.
Heavy herbivore pressure: Insects. Browsing animals. Anything that eats plants. Tropical environments support high biodiversity, including many species that would happily consume Trema leaves, stems, and flowers.
Humid conditions: Perfect for microbial growth. Bacteria, fungi, viruses all thrive in warm, moist environments. Plants growing in these conditions face constant pathogen pressure.
Disturbed habitats: Trema orientalis is a pioneer species. It colonizes cleared land, agricultural areas, forest edges—places with exposed soil and environmental stress.
Cannabinoids evolved to handle all of these challenges.
UV protection: Cannabinoids absorb ultraviolet light. They accumulate in trichomes on flower surfaces—exactly where seeds develop and where UV damage would be most harmful. Botanical sunscreen protecting the next generation.
Herbivore deterrence: Cannabinoids taste bitter. Some are toxic to insects and small animals. THC’s psychoactive effects are unpleasant for most non-human animals—they avoid plants that make them feel disoriented or sick.
Antimicrobial defense: This is the function people forget. Cannabinoids kill bacteria and fungi. They disrupt microbial cell membranes, interfere with cellular function, inhibit growth.
Plants don’t have immune systems like animals. They can’t produce antibodies or white blood cells. Instead, they produce chemical defenses.
Cannabinoids are part of that chemical arsenal.
For Trema orientalis growing in humid tropical conditions with constant microbial threats, producing antimicrobial compounds is essential for survival.
The plant makes cannabinoids to fight infections.
And we can use them for the same purpose.
If these compounds protect plants from bacterial and fungal pathogens across millions of years of evolution, if they work effectively enough to be naturally selected and maintained in multiple plant lineages, maybe they can help humans too.
Traditional Thai healers figured this out empirically, through centuries of observation and practice.
Modern science just confirmed the mechanism.
The Evolutionary Logic
Three Trema species now confirmed to produce cannabinoids:
1. Trema orientalis (Thailand, tropical Asia) – peer-reviewed, published 2021
2. Trema micrantha (Brazil, South America) – preliminary findings, 2023
3. A related Trema species (also Thailand) – mentioned in the 2021 study
All three grow in tropical or subtropical regions.
All three face high UV exposure, heavy insect herbivore pressure, and humid conditions where pathogens flourish.
All three produce cannabinoids as part of their defensive strategy.
This is convergent evolution at work.
When unrelated organisms face similar environmental pressures, natural selection favors similar solutions. The trait evolves independently in multiple lineages because it works.
Classic examples: wings in birds, bats, and insects. Eyes in vertebrates and cephalopods. Echolocation in bats and dolphins.
Now add cannabinoid production in Cannabis and Trema to the list.
These plant genera are related—they’re in the same family (Cannabaceae)—but they’re not the same genus. They diverged millions of years ago. Different evolutionary paths. Different geographic distributions.
Yet both evolved to produce the same compounds.
Why? Because those compounds solve critical survival problems.
UV radiation threatens reproductive success. Herbivores threaten survival. Pathogens threaten health.
Cannabinoids address all three.
And the solution works well enough that natural selection has maintained and refined cannabinoid production across multiple plant species over millions of years.
Evolution has been testing cannabinoids as antimicrobials far longer than humans have been doing clinical trials.
The results? They work.
Against plant pathogens. Against animal pathogens. Against bacteria that have evolved resistance to our most advanced synthetic antibiotics.
Regional Variation: Environmental Pressure Shapes Chemistry
One fascinating detail from the Thailand study: cannabinoid profiles varied significantly by region.
Northern Thailand (agricultural areas, forest edges):
- Highest CBN: 357 mg/kg
- Highest THC: 90 mg/kg
- No CBD detected
Southeastern Thailand (coastal beach forests):
- Moderate CBN: 50-55 mg/kg
- No THC detected
- No CBD detected
Southern Thailand (agricultural and disturbed areas):
- Moderate CBN: 140 mg/kg
- Moderate THC: 38 mg/kg
- Low CBD: 2-5 mg/kg
Different environments. Different pathogen pressures. Different herbivore communities. Different cannabinoid profiles.
This isn’t random variation. It’s optimization.
Plants in northern agricultural areas—high human disturbance, intensive cultivation nearby, heavy pest pressure—produced the highest concentrations of both CBN and THC. Maximum defense in maximum stress environment.
Coastal beach forest plants—more stable ecosystem, less human disturbance, different environmental stressors—produced only CBN, no THC or CBD. Different threat profile, different defensive chemistry.
Southern plants in disturbed areas—moderate stress, varied conditions—showed moderate levels of all three cannabinoids. Broad-spectrum defense for variable threats.
The plant is responding to its environment. Producing the specific defensive compounds most useful for the specific challenges it faces.
This is biochemical adaptation in real time.
And it tells us something important: cannabinoid production isn’t fixed. It’s dynamic. Responsive. Context-dependent.
The same species in different environments produces different cannabinoid profiles because those profiles solve different problems.
Nature doesn’t make excess. It makes what’s needed.
What This Means for Cannabinoid Research
The Thailand study changes several assumptions about cannabinoids.
First: Cannabinoids aren’t unique to cannabis. We now have multiple confirmed examples of non-cannabis plants producing THC, CBD, and CBN. The compounds aren’t “cannabis compounds.” They’re defensive phytochemicals that multiple plant species have evolved to produce.
Second: CBN deserves more research attention. Most cannabinoid research focuses on CBD (for wellness applications) or THC (for recreational/medical use and because it’s the psychoactive compound driving prohibition). CBN is understudied. But Trema orientalis produces CBN as its primary cannabinoid, and that CBN shows potent antibacterial activity. How many other CBN applications are we missing because we’re focused on the other cannabinoids?
Third: Traditional medicine knowledge is valuable. The Thai study didn’t start with random screening. The researchers knew Trema orientalis was used traditionally for infections. They looked for antimicrobial activity because traditional healers told them it would be there. How much other ethnobotanical knowledge could guide modern research if we paid attention?
Fourth: Plant chemistry is more sophisticated than we give it credit for. The regional variation in Trema cannabinoid profiles shows active adaptation to environmental pressures. Plants aren’t just making compounds randomly. They’re solving specific problems with specific solutions. Understanding that logic helps us understand when and how these compounds might help humans.
Fifth: Evolution has done the hard work. Cannabinoids have been tested against bacterial and fungal pathogens for millions of years. Plants that couldn’t defend themselves died. Plants that produced effective antimicrobials survived and reproduced. Natural selection has been running clinical trials on cannabinoid antimicrobial efficacy since before humans existed. Maybe we should look at the results.
The Credibility Gap
Here’s what bothers me about the media coverage.
Brazil announces a preliminary finding—CBD in Trema micrantha, not yet peer-reviewed, no published methodology, just early results from a research grant—and it gets headlines. “Nature made CBD twice!” “Legal alternatives to cannabis!” “New CBD sources discovered!”
Meanwhile, Thailand published a complete, peer-reviewed study in 2021. Full methodology documented. Reproducible results across nine plant specimens from three different regions. Chemical analysis with GC-MS. Antibacterial testing following clinical standards. Published in a respected journal (PeerJ).
And almost nobody noticed.
Why? Because the antibacterial angle is less sexy than “CBD without cannabis.”
But the antibacterial findings are more significant.
Finding cannabinoids in another plant is interesting from an evolutionary biology perspective. It tells us about convergent evolution and phytochemistry.
Finding cannabinoids that kill drug-resistant bacteria is useful from a medical perspective. It tells us about potential therapeutic applications.
One is scientifically fascinating. The other could save lives.
The WHO lists antimicrobial resistance as one of the top ten global public health threats. Bacteria are developing resistance faster than we’re developing new antibiotics. By 2050, drug-resistant infections could kill 10 million people annually—more than cancer currently kills.
We need new antimicrobial agents. Desperately.
And here’s a peer-reviewed study showing that plant cannabinoids—from a common tropical shrub that grows like a weed—inhibit MRSA, Pseudomonas, and Acinetobacter at clinically relevant concentrations.
That should be the headline.
Not “legal CBD alternatives” but “nature’s antibiotics proven effective against superbugs.”
But here we are.
Looking Forward
The Thailand research opens several avenues for future investigation.
Cannabinoid mechanisms: How exactly do cannabinoids disrupt bacterial cell membranes? What specific membrane components do they target? Can we optimize the structure for enhanced antibacterial activity?
Resistance development: Will bacteria develop resistance to cannabinoids the way they’ve developed resistance to conventional antibiotics? If so, how quickly? Can cannabinoids be used in combination with other antimicrobials to prevent resistance?
Clinical applications: Can cannabinoid extracts be developed into topical antibacterial treatments for skin infections? Could they be used for respiratory infections as traditional medicine suggests? What about systemic infections?
Other Trema species: How many other plants in the genus produce cannabinoids? What about other genera in the Cannabaceae family? Is cannabinoid production widespread in this family, or limited to specific lineages?
Other antimicrobial compounds: Cannabinoids weren’t the only compounds in the Trema extracts. What else is there? Are cannabinoids working alone or synergistically with other plant chemicals?
These are answerable questions. They require research funding, lab time, clinical trials. But the preliminary evidence is solid.
Traditional medicine has been using Trema orientalis for infections for centuries.
Chemical analysis found antimicrobial cannabinoids in the plant.
Lab testing confirmed those cannabinoids kill drug-resistant bacteria.
The foundation is there. The validation is complete.
Now we need to build on it.
Final Thoughts
Next time someone dismisses cannabinoids as “cannabis hype” or “wellness trend,” remember Thailand.
Peer-reviewed science. Published methodology. Reproducible results.
Multidrug-resistant bacteria. Clinical antimicrobial testing standards. Measurable inhibition at pharmaceutical-relevant concentrations.
Traditional medicine knowledge validated by modern research.
Plants producing antimicrobial compounds because evolution selected for them over millions of years.
This isn’t hype. This is biology.
Nature has been working on cannabinoids as antimicrobial agents far longer than we’ve been working on synthetic antibiotics.
Maybe it’s time we paid attention to what nature has already figured out.
The Brazil discovery was interesting. Three cheers for convergent evolution.
But Thailand? Thailand proved it works.
And that’s the story everyone should be talking about.
Read the full peer-reviewed study: Napiroon et al., 2021. “Cannabinoids from inflorescences fractions of Trema orientalis (L.) Blume (Cannabaceae) against human pathogenic bacteria.” PeerJ 9:e11446.
