Background
Researchers at Johns Hopkins University discovered that broccoli sprouts and other cruciferous vegetable sprouts contain exceptionally high concentrations of glucosinolates — compounds that induce Phase 2 detoxification enzymes in the body that help neutralize carcinogens. Based on this discovery, Brassica Protection Products LLC and Johns Hopkins obtained three U.S. patents covering methods of preparing and consuming cruciferous sprout food products described as “rich in glucosinolates” for the purpose of reducing cancer risk.
Several sprout producers sued for a declaration that the patents were invalid. The district court granted summary judgment of invalidity, finding that the patents were anticipated by prior art: before the patent applications were filed, the prior art already described how to germinate broccoli seeds into sprouts and consume those sprouts as food. The fact that Brassica’s researchers had discovered a previously unrecognized beneficial property — the glucosinolate content and its cancer-prevention potential — did not change the fact that those properties were inherent characteristics of the sprouts grown by the prior art methods. Brassica and Johns Hopkins appealed.
The Court’s Holding
The Federal Circuit affirmed the invalidity ruling in an opinion authored by Judge Prost. The court’s analysis proceeded on two key issues: claim construction and inherent anticipation.
On claim construction, the court examined the preamble phrase “rich in glucosinolates,” which Brassica argued was not a claim limitation at all, or alternatively should be construed to require specific numerical thresholds of glucosinolate concentration drawn from the specification. The court held that the preamble was limiting because it gave meaning and purpose to the structural method steps and was reinforced by the prosecution history. However, the court rejected the attempt to import specific numerical thresholds from the specification into the claim, instead construing “rich” and “high” in their ordinary comparative sense — meaning not low in glucosinolates. This moderate construction helped Brassica somewhat, but ultimately did not save the patents.
On inherent anticipation, the Federal Circuit reaffirmed the foundational doctrine: prior art anticipates a patent claim not only when it expressly discloses every claim limitation, but also when the claim limitations are necessarily present — inherent — in the prior art process or product, even if those properties were not recognized at the time. Cruciferous sprouts grown by the methods described in the prior art inherently contained high levels of glucosinolates and inherently induced Phase 2 detoxification enzymes. The court applied the key principle from settled anticipation law: “It matters not that those of ordinary skill heretofore may not have recognized the inherent characteristics of the prior art.” Discovery of a previously unrecognized but naturally existing property of known subject matter does not constitute patentable invention.
Key Takeaways
- The inherent anticipation doctrine holds that prior art anticipates a claim when every limitation of the claim is necessarily present in the prior art, even if those properties or characteristics were not recognized or appreciated at the time of the prior art disclosure.
- Discovering a previously unknown beneficial property of a known substance, method, or composition does not entitle the discoverer to a patent on that substance, method, or composition — the claimed subject matter was already in the prior art, even if its beneficial characteristics were not yet understood.
- Preamble language in patent claims that provides purpose or context to the method steps or structural elements is generally construed as limiting, particularly when reinforced by the specification and prosecution history.
- Courts will not import specific numerical parameters from the specification into claim terms unless the claim language or prosecution history makes clear that the inventor intended such limitations — a qualitative term like “rich” carries its ordinary comparative meaning, not specification-specific thresholds.
- Patent protection is available for inventions, not for the discovery of preexisting natural characteristics of known materials or processes — the line between invention and discovery is a fundamental constraint on patentability.
Why It Matters
In re Cruciferous Sprout Litigation is an instructive case on the scope and operation of inherent anticipation — one of the most important and sometimes counterintuitive doctrines in patent law. Inherent anticipation allows prior art to defeat a patent claim even when the prior art reference does not expressly describe the claimed limitation, as long as the limitation is necessarily present whenever the prior art is practiced. This doctrine prevents patent owners from claiming exclusive rights over properties that, while previously unrecognized, were already present in the public domain.
The case has particular relevance in the life sciences, where researchers frequently discover previously unknown beneficial properties of known natural substances. The discovery that broccoli sprouts contain unusually high concentrations of cancer-fighting compounds was scientifically significant and commercially valuable. But because broccoli sprouts were already a known food product, and the high glucosinolate content was an inherent property of those sprouts rather than something created by the inventors, the patents could not validly claim the methods of growing and consuming them. For practitioners and companies developing natural product-based innovations, the case underscores that patent protection for discovery of inherent natural properties requires focusing claims on novel methods of application, new formulations, or new preparations that go beyond the prior art — not on the natural properties themselves.